JP2016084389A - Adhesive composition and adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition and an adhesive sheet capable of enhancing adhesiveness to a cured article and having a phase separation structure, which provides high strength by proceeding with fracture along with a border of separated phase each other during cohesive failure of the cured article by an applied external force.SOLUTION: There is provided an adhesive composition containing an acrylic polymer, an epoxy thermosetting resin and a thermosetting agent, a cured article obtained by curing the adhesive composition has a phase separation structure and the phase separation structure of the cured article has a first correlation length Lof 1.2 μm or less and a second correlation length Lof 6.5 μm or more.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive composition and an adhesive sheet.

The phase separation structure in the cured adhesive is important for adhesive properties. Conventionally, it is known that when an external force is applied and the cured product undergoes cohesive failure, the breakage proceeds along the boundary between separated phases, and high strength is obtained.
For example, Patent Document 1 discloses that when an adhesive composition containing a predetermined epoxy resin, a polymer compound having an epoxy group, and an epoxy curing agent is cured, phase separation occurs and a structural period is 0.01 μm or more. It is described that a phase separation structure of less than 0.5 μm is formed.
For example, Patent Document 2 discloses a cured epoxy resin obtained by curing an epoxy resin composition containing an epoxy resin as a matrix resin and carbon fibers, and has a structural period of 1 nm to 5 μm. A cured epoxy resin having a phase separation structure is described.

Japanese Patent No. 5109572 JP 2014-122121 A

  Although the resin hardened | cured material which has the phase-separation structure of a predetermined structure period like patent document 1 and 2 is disclosed, the adhesive composition which can express high adhesiveness after hardening rather than the conventional adhesive composition Things are sought.

  The objective of this invention is providing the adhesive composition and adhesive sheet which can improve the adhesiveness of hardened | cured material.

According to one aspect of the present invention, an adhesive composition comprising an acrylic polymer, an epoxy thermosetting resin, and a thermosetting agent,
The cured product obtained by curing the adhesive composition has a phase separation structure,
Phase separation structure of the cured product, the adhesive composition is provided, characterized in that it comprises the following first correlation length L _1, and 6.5μm or more second correlation length L ₂ 1.2 [mu] m .

In the above-described adhesive composition according to one aspect of the present invention, the first correlation length L ₁ is calculated by the following mathematical formula (Formula 1), and the second correlation length L ₂ is calculated by the following mathematical formula (Formula 2). ) Is preferably calculated.
L ₁ = 2π / q ₁ ≦ 1.2 μm (Equation 1)
L ₂ = 2π / q ₂ ≧ 6.5 μm (Expression 2)
(In the mathematical formula (Equation 1), q ₁ observes the surface phase image of the cured product using a scanning probe microscope, and performs a two-dimensional fast Fourier transform on the surface phase image to obtain a Fourier transform image. And obtaining a one-dimensional intensity distribution profile indicating the relationship of the intensity to the wave number based on the Fourier transform image, and the wave number indicating the first peak in the one-dimensional intensity distribution profile (unit: μm ⁻¹ ). ,
In the mathematical formula (Equation 2), q ₂ is a wave number (unit: μm ⁻¹ ) indicating the second peak in a wave number region lower than the first peak. )

  The adhesive composition according to one embodiment of the present invention preferably further includes a silane compound.

  Moreover, according to 1 aspect of this invention, the adhesive sheet characterized by having an adhesive layer containing the adhesive composition which concerns on the above-mentioned this invention, and a base material is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition and adhesive sheet which can improve the adhesiveness of hardened | cured material can be provided.

It is a surface phase image of the hardened | cured material of the adhesive composition which concerns on an Example and a comparative example. 2 is a surface phase image obtained by narrowing the observation region as compared with FIG. It is a Fourier transform image obtained by performing two-dimensional fast Fourier transform on the surface phase image. It is a one-dimensional intensity distribution profile of the said hardened | cured material which concerns on an Example. It is the said one-dimensional intensity distribution profile after correction | amendment.

[Adhesive composition]
The adhesive composition of the present embodiment includes a first resin component, a second resin component, and a thermosetting agent. A cured product obtained by curing the adhesive composition of the present embodiment has a phase separation structure exhibiting a predetermined structural periodicity. The first resin component contained in the adhesive composition of this embodiment is preferably an acrylic polymer, and the second resin component is preferably an epoxy thermosetting resin. The adhesive composition of the present embodiment is preferably a tacky adhesive composition that has tackiness before curing and is cured by heat to improve adhesive strength.

  Examples of the phase separation structure include a sea-island structure and a co-continuous structure. The sea-island structure has a continuously connected sea (continuous phase) and islands (dispersed phase), and the sea is dotted with islands. The co-continuous structure is a structure in which each phase separated is a three-dimensional continuous phase.

The phase separation structure of the cured product has a first correlation length L ₁ of 1.2 μm or less and a second correlation length L ₂ of 6.5 μm or more. First correlation length L ₁ is calculated by the following equation (Equation 1), the correlation length L ₂ of the second is preferably calculated by the following equation (Equation 2).
L ₁ = 2π / q ₁ ≦ 1.2 μm (Equation 1)
L ₂ = 2π / q ₂ ≧ 6.5 μm (Expression 2)

In the formula (Equation 1), q ₁ is a surface phase image of the cured product observed using a scanning probe microscope, and a two-dimensional fast Fourier transform is performed on the surface phase image to obtain a Fourier transform image. Then, a one-dimensional intensity distribution profile indicating the relationship of intensity to wave number is obtained based on the Fourier transform image, and the wave number (unit: μm ⁻¹ ) indicating the first peak in the one-dimensional intensity distribution profile. In the formula (Equation 2), q ₂ is a wave number (unit: μm ⁻¹ ) indicating a second peak in a wave number region lower than the first peak in the one-dimensional intensity distribution profile.

  As the scanning probe microscope (SPM), for example, a scanning tunneling microscope (STM), an atomic force microscope (AFM) using atomic force, or the like may be used. preferable. In the atomic force microscope, the dynamic force mode (DFM) is used to measure the shape while controlling the distance to the sample surface so that the vibration amplitude of the lever becomes constant in a state where the cantilever as the sensor unit is resonated. It is more preferable to observe the cured product. When observing the surface phase image of the cured product with a scanning probe microscope, the observation region is not particularly limited, but is set to a square of 125 μm in length and 125 μm in width, for example.

A two-dimensional fast Fourier transform (FFT) is performed on the surface phase image. The two-dimensional fast Fourier transform is performed using a computer equipped with image analysis software. For example, ImageJ (manufactured by National Institutes of Health (NIH)) or the like is used as the image analysis software.
When the two-dimensional fast Fourier transform process is performed, the position information of light and shade in the surface phase image is converted into periodic information, and a Fourier transform image is obtained. Furthermore, the one-dimensional intensity distribution profile is obtained by averaging the intensity in the Fourier transform image in the azimuth direction. In this one-dimensional intensity distribution profile, the vertical axis is intensity (unit is arbitrary unit (au)), and the horizontal axis is wave number (unit is μm ⁻¹ ). The one-dimensional intensity distribution profile obtained for the cured product shows two or more peaks. Background correction processing is preferably performed on the one-dimensional intensity distribution profile.
In the present embodiment, in the one-dimensional intensity distribution profile, the peak on the high wave number side is the first peak, the wave number indicating the first peak is q ₁ , and the peak on the low wave number side of the first peak is the first peak. the second peak, wave number that indicates the second peak is q _2. The first correlation length L ₁ and the second correlation length L ₂ are calculated based on the obtained wave number q _1, wave number q _{2 and the} above-described mathematical expressions (Expression 1) and (Expression 2). As a criterion for determining the presence of a peak, an exponential function, which will be described later, is selected as the background, and when the background is subtracted from the obtained one-dimensional intensity distribution profile, an upwardly convex shape is present, before and after the maximum value. When the slope of the tangent line changes from negative to positive, it can be determined that it is a peak.

The first correlation length L ₁ is greater than 0.01 μm, preferably 0.1 μm or more and 1.2 μm or less, and more preferably 1.0 μm or more and 1.2 μm or less. When L ₁ is 0.01 μm or less, it becomes equal to the inertial radius of one of the polymers as the composition, so that the phase is not formed and the intended structure cannot be obtained.
Correlation length _{L 2} of the second is preferably at least 7.0 .mu.m, and more preferably not less than 7.5 [mu] m. The second correlation length _{L 2} is preferably at 125μm or less, more preferably 40μm or less, more preferably 10μm or less.
The ratio of L ₁ to L ₂ (L ₂ / L ₁ ) is preferably 6.5 / 1.2 = 5.4 or more, and more preferably 7.5 or more.

The adhesive composition according to this embodiment may further have a correlation length within a predetermined range in the phase separation structure of the cured product. For example, you may have _3rd correlation length L3. When the third peak giving the third correlation length L ₃ is observed in the one-dimensional intensity distribution profile, the wave number q ₃ (unit is μm ⁻¹ ) indicating the third peak and the following mathematical formula (Formula 3) ) on the basis of the third correlation length L ₃ of is calculated.
L ₃ = 2π / q ₃ (Equation 3)
The third correlation length L ₃ is preferably larger than 125 μm, and in this case, the second correlation length L ₂ is preferably 125 μm or less.

Factors for forming a phase separation structure having two or more correlation lengths defined in the above range include, for example, the viscosity of the adhesive composition, the reactivity of the adhesive composition, and the adhesive composition. The number of hydroxyl groups and aromatic rings, curing conditions, etc. are presumed at this time. However, the present invention is not limited to these inferred factors. The adhesive composition of the present invention, the cured product may have a phase separation structure which satisfies the relationship of the correlation length L ₁ and L ₂ above.

(Acrylic polymer (A))
A conventionally well-known acrylic polymer can be used as an acrylic polymer (A).
The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably from 10,000 to 2,000,000, more preferably from 100,000 to 1,500,000. If the Mw of the acrylic polymer (A) is 10,000 or more, a semiconductor produced when the adhesive force between the adhesive layer and the substrate is too strong when the adhesive composition is used for a dicing sheet or the like as a semiconductor material. Chip pickup defects can be reduced. If Mw of an acrylic polymer (A) is 2 million or less, it becomes easy for an adhesive layer to follow the unevenness | corrugation of a to-be-adhered body, and generation | occurrence | production of a void etc. can be suppressed.
Mw of the acrylic polymer (A) is a polystyrene equivalent value measured by a gel permeation chromatography (GPC) method.

The glass transition temperature (Tg) of the acrylic polymer (A) is preferably -60 ° C or higher and 70 ° C or lower, and more preferably -30 ° C or higher and 50 ° C or lower. If the Tg of the acrylic polymer (A) is −60 ° C. or more, the pickup failure of the semiconductor chip can be reduced as described above. When the acrylic polymer (A) has a Tg of 70 ° C. or lower, sufficient adhesive strength for fixing the wafer can be obtained when the adhesive composition is used for a dicing sheet or the like.
The Tg of the acrylic polymer (A) is calculated from the Tg of the homopolymer of the monomer constituting the acrylic polymer (A) using the Fox equation.

Examples of the monomer constituting the acrylic polymer (A) include (meth) acrylic acid alkyl ester, (meth) acrylic acid ester having a cyclic skeleton, (meth) acrylic acid ester having a hydroxyl group, and acrylic acid having a glycidyl group. Examples thereof include esters and unsaturated carboxylic acids.
As the (meth) acrylic acid alkyl ester, for example, the alkyl group preferably has 1 to 18 carbon atoms, and more specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, Examples thereof include propyl (meth) acrylate and butyl (meth) acrylate.
Examples of the (meth) acrylic acid ester having a cyclic skeleton include (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclo Examples thereof include pentenyloxyethyl acrylate and imide acrylate.
Examples of the (meth) acrylic acid ester having a hydroxyl group include hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate.
Examples of the acrylate ester having a glycidyl group include glycidyl acrylate and glycidyl methacrylate.
As unsaturated carboxylic acid, acrylic acid, methacrylic acid, itaconic acid etc. are mentioned, for example.
The monomer constituting the acrylic polymer (A) may be one type or two or more types.

As the monomer constituting the acrylic polymer (A), it is preferable to use a (meth) acrylic acid ester having at least a hydroxyl group. By using a (meth) acrylic acid ester having a hydroxyl group as a monomer constituting the acrylic polymer (A), compatibility with the epoxy thermosetting resin (B) is improved.
In this case, the structural unit derived from the (meth) acrylic acid ester having a hydroxyl group is preferably contained in the range of 1% by mass or more and 20% by mass or less in the acrylic polymer (A). More preferably, it is contained in the range of% or less.
Specifically, the acrylic polymer (A) is preferably a copolymer of (meth) acrylic acid alkyl ester and (meth) acrylic acid ester having a hydroxyl group.

  In addition to the above (meth) acrylic acid ester and derivatives thereof, for example, vinyl acetate, acrylonitrile, styrene, or the like may be used as a raw material monomer for the acrylic polymer (A) as long as the object of the present invention is not impaired. .

(Epoxy thermosetting resin (B))
As the epoxy thermosetting resin (B), various conventionally known epoxy resins can be used. Examples of the epoxy thermosetting resin (B) include an epoxy resin containing two or more functional groups in one molecule. For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenylene skeleton type epoxy resin, Phenol novolac epoxy resin, cresol novolac epoxy resin, polyfunctional epoxy resin, dicyclopentadiene epoxy resin, biphenyl epoxy resin, triphenolmethane epoxy resin, heterocyclic epoxy resin, stilbene epoxy resin, and condensation Examples thereof include cyclic aromatic hydrocarbon-modified epoxy resins, and halides of these epoxy resins.
These epoxy resins may be used alone or in combination of two or more.

  The epoxy equivalent of the epoxy resin is not particularly limited, but is preferably 150 g / eq or more and 1000 g / eq or less. The epoxy equivalent is a value measured according to JISK7236.

In the adhesive composition of the present embodiment, the content of the epoxy thermosetting resin (B) is preferably 1 part by mass or more and 1500 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (A). It is more preferably 3 parts by mass or more and 1000 parts by mass or less, and further preferably 100 parts by mass or more and 1000 parts by mass or less.
If content of an epoxy-type thermosetting resin (B) is 1 mass part or more, the adhesive bond layer which has higher adhesive force will be obtained. Further, if the content of the epoxy thermosetting resin (B) is 1500 parts by mass or less, the adhesive force between the base material and the adhesive layer is too strong when used for a dicing sheet or the like as described above. The pick-up failure of the semiconductor chip can be reduced.

(Thermosetting agent (C))
The thermosetting agent (C) functions as a thermosetting agent for the epoxy thermosetting resin (B).
As a thermosetting agent (C), the compound which has 2 or more of functional groups which can react with an epoxy group in a molecule | numerator is mentioned. Examples of the functional group include a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group, and an acid anhydride group. In these, a phenolic hydroxyl group, an amino group, and an acid anhydride group are preferable, and a phenolic hydroxyl group and an amino group are more preferable.

Specific examples of the thermosetting agent (C) include a phenol thermosetting agent and an amine thermosetting agent. Examples of the phenol-based thermosetting agent include novolak-type phenol resins, dicyclopentadiene-based phenol resins, polyfunctional phenol resins, and aralkyl phenol resins. Examples of the amine thermosetting agent include dicyandiamide (DICY).
A thermosetting agent (C) may be used individually by 1 type, and may use 2 or more types together.

In the adhesive composition of the present embodiment, the content of the thermosetting agent (C) is 0.1 parts by mass or more and 500 parts by mass or less with respect to 100 parts by mass of the epoxy thermosetting resin (B). Is preferably 1 part by mass or more and 200 parts by mass or less.
If content of a thermosetting agent (C) is 0.1 mass part or more, it can prevent that the sclerosis | hardenability of adhesive composition is insufficient, As a result, the adhesive bond layer which has higher adhesive force is obtained. . If content of a thermosetting agent (C) is 500 mass parts or less, it can suppress that the hygroscopic property of adhesive composition increases, for example, adhesive composition is used for adhesive layers, such as a dicing die bonding sheet. If this occurs, it is possible to suppress a decrease in reliability of the semiconductor package due to moisture absorption.

(Silane compound (D))
It is preferable that the adhesive composition of this embodiment further contains a silane compound (D). If the adhesive composition contains the silane compound (D), the adhesive force to the adherend can be further improved. In addition, by using the silane compound (D), the adhesive properties of the cured product can be maintained even when moisture absorption is performed without impairing the heat resistance of the cured product obtained by curing the adhesive composition. can do.

  As the silane compound (D), a compound having a group that reacts with a functional group of the acrylic polymer (A), the epoxy thermosetting resin (B), or the like is preferably used. As the silane compound (D), a silane coupling agent is preferable.

  Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacrylo). Propyl) trimethoxysilane, γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-6- (aminoethyl) -γ-aminopropylmethyldiethoxysilane, N -Phenyl-γ-aminopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis (3-triethoxysilylpropyl) tetrasulfane, methyltri Methoxysilane, me Examples include tiltriethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane.

Moreover, the oligomer type silane coupling agent which is a product condensed by hydrolysis and dehydration condensation of an alkoxy group may be used. For example, an oligomer produced by dehydration condensation of a low-molecular silane compound having two or three alkoxy groups and a low-molecular silane compound having four alkoxy groups is rich in reactivity of the alkoxy group and sufficient Since it has several organic functional groups, it is preferable.
Examples of the low molecular silane compound having two or three alkoxy groups include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ -(Methacrylopropyl) trimethoxysilane and the like.
Examples of the low-molecular silane compound having four alkoxy groups include tetramethoxysilane and tetraethoxysilane.
Examples of the oligomer that is a copolymer include an oligomer that is a copolymer of poly-3- (2,3-epoxypropoxy) propylmethoxysiloxane and polydimethoxysiloxane.
A silane coupling agent may be used individually by 1 type, and may use 2 or more types together.

  In the adhesive composition of this embodiment, the content of the silane compound (D) is 0.1 parts by mass with respect to a total of 100 parts by mass of the acrylic polymer (A) and the epoxy thermosetting resin (B). The amount is preferably 20 parts by mass or less. If content of a silane compound (D) is 0.1 mass part or more, the adhesive force with respect to a to-be-adhered body can further be improved. If content of a silane compound (D) is 20 mass parts or less, generation | occurrence | production of outgas can be suppressed.

(Curing accelerator (E))
The curing accelerator (E) is used for adjusting the curing rate of the adhesive composition. The curing accelerator (E) is preferably a compound that can accelerate the reaction between an epoxy group and a phenolic hydroxyl group or an amine. Specific examples of this compound include tertiary amines, imidazoles, organic phosphines, and tetraphenylboron salts.
Examples of tertiary amines include triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, and tris (dimethylaminomethyl) phenol.
Examples of imidazoles include 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4,5-hydroxy. And methyl imidazole.
Examples of organic phosphines include tributylphosphine, diphenylphosphine, and triphenylphosphine.
Examples of the tetraphenylboron salt include tetraphenylphosphonium tetraphenylborate and triphenylphosphine tetraphenylborate.
In addition, the hardening accelerator (E) contained in the adhesive composition of the present invention may be a single type or a combination of two or more types.

  In the adhesive composition of this embodiment, the curing accelerator (E) is 0.001 part by mass or more with respect to a total of 100 parts by mass of the epoxy thermosetting resin (B) and the thermosetting agent (C). 100 parts by mass or less is preferably contained, more preferably 0.01 parts by mass or more and 50 parts by mass or less, and still more preferably 0.1 parts by mass or more and 10 parts by mass or less.

(Energy ray polymerizable compound (F))
The adhesive composition of this embodiment may contain an energy ray polymerizable compound (F). By polymerizing the energy ray polymerizable compound (F) by energy ray irradiation, the adhesive force of the adhesive layer in the adhesive sheet can be reduced. For this reason, delamination between the base material and the adhesive layer can be easily performed in the semiconductor chip pick-up process.

The energy beam polymerizable compound (F) is a compound that polymerizes and cures when irradiated with energy rays such as ultraviolet rays and electron beams. Examples of the energy ray polymerizable compound (F) include compounds having one or more energy ray polymerizable double bonds in the molecule, for example, acrylate compounds.
Examples of the acrylate compound include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, 1,4-butylene glycol diacrylate, 1, Examples include 6-hexanediol diacrylate, dicyclopentadiene dimethoxydiacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer.

The molecular weight (weight average molecular weight in the case of an oligomer or polymer) of the energy beam polymerizable compound (F) is preferably 100 or more and 30000 or less, and more preferably about 200 or more and 9000 or less.
In the adhesive composition of the present embodiment, the content of the energy beam polymerizable compound (F) is preferably 1 part by mass or more and 400 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (A). It is more preferably 3 parts by mass or more and 300 parts by mass or less, and further preferably 10 parts by mass or more and 200 parts by mass or less. When the content of the energy beam polymerizable compound (F) is 400 parts by mass or less with respect to 100 parts by mass of the acrylic polymer (A), the adhesive force of the adhesive layer to an organic substrate, a lead frame, or the like can be suppressed.

(Photopolymerization initiator (G))
When using the energy ray polymerizable compound (F) when using the adhesive composition of the present embodiment, irradiation with energy rays such as ultraviolet rays is performed, for example, between the substrate and the adhesive layer in the chip pickup process. It is preferable to reduce the adhesive force. By including the photopolymerization initiator (G) in the adhesive composition, the polymerization and curing time and the amount of light irradiation can be reduced.

Examples of the photopolymerization initiator (G) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, methyl benzoin benzoate, benzoin dimethyl ketal, 2,4 -Diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, 1,2-diphenylmethane, 2,4,6-trimethylbenzoyl Examples include diphenylphosphine oxide and β-chloranthraquinone.
A photoinitiator (G) may be used individually by 1 type, and may use 2 or more types together.

  The content of the photopolymerization initiator (G) is preferably 0.1 parts by mass or more and 10 parts by mass or less, and preferably 1 part by mass or more and 5 parts by mass with respect to 100 parts by mass of the energy beam polymerizable compound (F). The following is more preferable. If content of a photoinitiator (G) is 0.1 mass part or more, the fall of pick-up property by lack of photopolymerization can be suppressed. If content of a photoinitiator (G) is 10 mass parts or less, the production | generation of the residue which does not contribute to photopolymerization will be suppressed and an adhesive composition can fully be hardened.

(Inorganic filler (H))
The adhesive composition of this embodiment may further contain an inorganic filler (H).
By mix | blending an inorganic filler (H) with an adhesive composition, it becomes easy to adjust the thermal expansion coefficient of the hardened | cured material of this composition. By optimizing the thermal expansion coefficient of the adhesive layer after curing with respect to the semiconductor chip, the lead frame, and the organic substrate, the reliability of the semiconductor package can be further improved. In addition, the moisture absorption rate of the cured adhesive can also be reduced.

Examples of the inorganic filler (H) include powders such as silica, alumina, talc, calcium carbonate, titanium white, bengara, silicon carbide, and boron nitride, beads formed by spheroidizing them, single crystal fibers, and glass fibers. Is mentioned.
Among these, silica filler and alumina filler are preferable. An inorganic filler (H) may be used individually by 1 type, and may use 2 or more types together.
In the adhesive composition of this embodiment, the content of the inorganic filler (H) is usually 0% by mass or more and 80% by mass or less with respect to the entire adhesive composition.

(Other components (I))
The adhesive composition of this embodiment may contain various additives as necessary in addition to the components (A) to (H) described above. Examples of the various additives include flexible components such as polyester resins, plasticizers, antistatic agents, antioxidants, pigments, and dyes.

-Preparation of adhesive composition The adhesive composition of this embodiment is obtained by mixing the above-mentioned components at an appropriate ratio. At the time of mixing, each component may be previously diluted with a solvent and then mixed, or may be mixed while adding a solvent. Moreover, you may use, after diluting an adhesive composition with a solvent. Examples of the solvent include ethyl acetate, methyl acetate, diethyl ether, dimethyl ether, acetone, methyl ethyl ketone, acetonitrile, hexane, cyclohexane, toluene, and heptane.

[Adhesive sheet]
The adhesive sheet according to the present embodiment has a base material and an adhesive layer including the adhesive composition according to the above-described present embodiment. The adhesive layer is formed on the substrate. The shape of the adhesive sheet can take any shape such as a tape shape or a label shape.
As the base material of the adhesive sheet, for example, a paper material such as a synthetic resin film, high-quality paper, impregnated paper, glassine paper, and coated paper, or a sheet material such as nonwoven fabric, wood, and metal foil can be used. . Examples of synthetic resin films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film. , Polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, And a fluororesin film. In addition, examples of the base material of the adhesive sheet include these crosslinked films and laminated films. The surface of the base material may be subjected to an adhesive treatment by applying an adhesive. Examples of the pressure-sensitive adhesive used for the pressure-sensitive adhesive treatment of the substrate include acrylic, rubber-based, silicone-based, and urethane-based pressure-sensitive adhesives.
As the adhesive, it is preferable to use a removable adhesive. Examples of the releasable pressure-sensitive adhesive include a pressure-sensitive adhesive, a pressure-sensitive adhesive, an energy ray-curable pressure-sensitive adhesive, and a pressure-sensitive adhesive containing a thermal expansion component. By using a releasable pressure-sensitive adhesive, the base material and the adhesive layer are firmly fixed while the adherend is being processed, and then the adhesive layer is fixedly adhered to the adherend and removed from the base material. It becomes easy to peel.

  The adhesive sheet of the present embodiment is affixed to an adherend such as a semiconductor wafer, and after subjecting the adherend to necessary processing, the adhesive layer remains fixed on the adherend and is peeled off from the substrate. That is, the adhesive layer is suitably used for a process including a step of transferring the adhesive layer from the base material to the adherend. For this reason, the surface tension of the surface in contact with the adhesive layer of the substrate is preferably 40 mN / m or less, more preferably 37 mN / m or less, and even more preferably 35 mN / m or less. The lower limit of the surface tension of the surface in contact with the adhesive layer of the substrate is usually about 25 mN / m. Such a substrate having a low surface tension can be obtained by appropriately selecting the material, and can also be obtained by applying a release agent to the surface of the substrate and performing a release treatment.

The thickness of the base material in the adhesive sheet is preferably 10 μm or more and 500 μm or less, more preferably 15 μm or more and 300 μm or less, and further preferably 20 μm or more and 250 μm or less.
The thickness of the adhesive layer in the adhesive sheet is preferably 1 μm or more and 500 μm or less, more preferably 5 μm or more and 300 μm or less, and further preferably 10 μm or more and 150 μm or less.

The manufacturing method of an adhesive sheet is not specifically limited.
For example, an adhesive sheet may be produced by applying an adhesive composition on a substrate to form a coating film, and drying the coating film to form an adhesive layer. Moreover, you may manufacture an adhesive sheet by forming an adhesive bond layer on a peeling film and transferring this adhesive bond layer to a base material.

  The adhesive sheet may have a protective layer for protecting the adhesive layer. The protective layer is preferably provided so as to cover the adhesive layer on the substrate. The protective layer is preferably a release film, and the release film may be laminated on the adhesive layer. In addition, when the adhesive sheet is used in a semiconductor manufacturing process, an adhesive layer or an adhesive tape is separately provided on the outer periphery of the adhesive layer in order to fix other jigs such as a ring frame. Also good.

Cured adhesive composition according to the present embodiment has the specific phase separation structure of having a first correlation length L ₁ and the second correlation length L ₂ in the range described above, the high adhesion Have.
In the adhesive composition contained in the adhesive layer of the adhesive sheet according to the present embodiment, the cured product has the above-described specific phase separation structure, and thus has high adhesiveness.

The adhesive composition and the adhesive sheet of this embodiment are preferably used as a semiconductor material or an optical material, and more preferably a semiconductor adhesive composition and an adhesive sheet.
The adhesive composition of the present embodiment can be suitably used as a material for forming a so-called die bonding sheet and an adhesive layer constituting the dicing die bonding sheet, and is more preferably used for a dicing die bonding sheet.
The adhesive sheet of this embodiment can be suitably used as a die bonding sheet and a dicing die bonding sheet, and more preferably used as a dicing die bonding sheet.
If it is the adhesive composition of this embodiment, the hardened | cured material has the high adhesive force with respect to a to-be-adhered body even after passing through severe heat-humidity conditions and a reflow process in the manufacturing process of a semiconductor.

When using an adhesive composition and an adhesive sheet as a semiconductor material, during surface mounting in which the semiconductor device is heated using infrared rays, hot air, or the like, an adhesive and a metal material or organic substrate material that is an adherend in the semiconductor device Stress due to the difference in linear expansion coefficient from the layer is generated, and this stress is applied in the shear direction at the interface between the adhesive layer and the adherend. When stress is applied to the cured adhesive and a cohesive failure occurs, the failure progresses slowly at the start of braking when the failure occurs, and the failure surface rapidly advances into the material when the failure progresses.
If the adhesive composition and adhesive sheet of the present embodiment, since the phase separation structure having a first correlation length L ₁ and the second correlation length L ₂ of the structure periodicity in the cured product is formed, destruction Generation is suppressed, and the progress of destruction is also suppressed. As a result, high adhesion reliability that can withstand the above-described stress is exhibited. If second correlation length L ₂ is 6.5μm or more, the brake start time of the fracture progresses slowly, anchoring effect with fracture surface along the phase boundary is formed to obtain sufficient strength of expression It is thought that. If less than the first correlation length L ₁ is 1.2 [mu] m, when breaking progress destruction progresses rapidly, hardly destroyed plane through the phase is formed, an anchor effect is obtained, and sufficient strength is expressed Conceivable.

  The adhesive composition and adhesive sheet of the present embodiment exhibit high adhesiveness even when the adherend surface with which the adhesive layer is in contact is smooth. Conventionally, the average surface roughness Ra of the bonding surface of the semiconductor chip is about 120 μm, but in recent years, the semiconductor chip has been thinned and smoothed in order to maintain strength, and is practically used. With the adhesive composition and adhesive sheet of this embodiment, a semiconductor chip having an adhesive surface with an Ra of 120 μm or less can be mounted on an organic substrate, a lead frame, another semiconductor chip, or the like with a stronger adhesive force. Even if Ra is 10 nm or less, and even if Ra is about 5 nm, it can be mounted with a strong adhesive force.

[Modification of Embodiment]
In addition, this invention is not limited to the said embodiment, The deformation | transformation, improvement, etc. in the range which can achieve the objective of this invention are included in this invention.

  For example, the adhesive sheet may have an adhesive layer on both sides of the substrate. In this case, it is only necessary that at least one of the adhesive layers contains the adhesive composition according to the embodiment.

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

[1. Evaluation of structural periodicity of cured adhesives)
The adhesive layer of the adhesive sheet was cured to obtain a cured product. The adhesive layer was heated from room temperature at a temperature increase rate of 3 ° C./min, heated at 125 ° C. for 1 hour, further heated at a temperature increase rate of 3 ° C./min, and at 175 ° C. for 2 hours. Cured by heating.
The surface of the obtained cured product was observed using a scanning probe microscope (manufactured by Shimadzu Corporation, SPM-9700). Surface observation was performed in DFM mode. As a result of observation, a surface phase image of a region of 125 μm × 125 μm was obtained. The obtained surface phase image was subjected to two-dimensional fast Fourier transform (2D-FFT) using image analysis software ImageJ (manufactured by National Institutes of Health, USA), and the position information of the light and shade of the image was converted into periodic information. Next, a one-dimensional intensity distribution profile in the radial direction was obtained by averaging in the azimuth direction. In the one-dimensional intensity distribution profile, the horizontal axis is wave number (unit is μm ⁻¹ ), and the vertical axis is intensity (unit is arbitrary unit (au)).

Background correction represented by an exponential function was performed on the obtained one-dimensional intensity distribution profile. First, the total wave number region was fitted by the following mathematical formula (Formula 4) to obtain a background value.
(Background) = A × exp (−B × q) + C (Equation 4)
In the mathematical formula (Equation 4), A is a coefficient for correcting the scale with respect to the entire intensity, B is a coefficient that directly indicates the dependence of the wave number, and C is a high coefficient of the entire intensity. Is a coefficient for correcting the thickness, and q is each wave number. When fitting with the equation (Equation 4), the parameters A, B, and C are set so that the sum of the squares of the difference between the intensity obtained from the analysis at each wave number q and the equation (Equation 4) becomes a minimum value. It was determined. In the present embodiment, the solver function provided in Excel (registered trademark) manufactured by Microsoft Corporation is used in the determination of each parameter A, B, and C. However, other software may be used.
The inclination was corrected by subtracting the background from the one-dimensional intensity distribution profile. The first correlation length L ₁ and the second correlation length L ₂ were calculated based on the wave numbers indicating the peaks q ₁ and q ₂ in the profile after correction and the above-described mathematical expressions (Equation 1) and (Equation 2).

[2. (Tensile strength test)
The tensile strength test was performed using a universal tensile tester 5581 series (manufactured by Instron).
In the measurement sample, an adhesive layer having a thickness of about 40 μm was first obtained by superimposing an adhesive layer having a thickness of 40 μm, and then the adhesive layer was thermally cured, and the cured product was rectangular-shaped with a size of 150 mm × 15 mm. It was produced by cutting into a shape. The adhesive layer was heated from room temperature at a temperature increase rate of 3 ° C./min, heated at 125 ° C. for 1 hour, further heated at a temperature increase rate of 3 ° C./min, and at 175 ° C. for 2 hours. Cured by heating.
The produced measurement sample was attached to a testing machine. At this time, the distance between the supports for supporting the measurement sample was adjusted to 100 mm. The tensile speed was 0.5 mm / min or 30 mm / min. The strength when the measurement sample was broken was determined. The obtained strength was divided by the cross-sectional area of the measurement sample and converted to stress (unit: MPa). The temperature of the measurement environment was 250 ° C.

[3. (Shear strength test)
(3-1) Production of upper chip A dry polishing process was performed on the surface of the silicon wafer by a wafer backside grinding apparatus (DGP 8760, manufactured by DISCO Corporation). The adhesive sheet is affixed to the dry-polished surface of the treated silicon wafer (200 mm diameter, 500 μm thick) using a tape mounter (Adwill RAD-2500 m / 8, manufactured by Lintec Corporation), and a ring frame Fixed to. Then, the ultraviolet-ray was irradiated from the base-material surface side of the said adhesive sheet using the ultraviolet irradiation device (The Lintec Co., Ltd. product, Adwill RAD-2000). The ultraviolet irradiation conditions were 350 mW / cm ² and 190 mJ / cm ² .
Next, the silicon wafer was diced into chips having a size of 5 mm × 5 mm using a dicing apparatus (manufactured by DISCO Corporation, DFD651). The amount of cut at the time of dicing was cut at a depth of 20 μm from the chip side with respect to the base material of the adhesive sheet. After dicing, the chip was picked up from the substrate together with the adhesive layer of the adhesive sheet to obtain an upper chip. Adwill is a registered trademark.

(3-2) Preparation of test specimen for measurement Dicing tape (manufactured by Lintec Corporation) on a silicon wafer (200 mm diameter, thickness 725 μm) coated with polyimide resin (manufactured by Hitachi Chemical DuPont Microsystems Co., Ltd., PLH708) Adwill D-650) was attached using a tape mounter in the same manner as in (3-1) above, and was diced to a chip size of 12 mm × 12 mm using a dicing apparatus and picked up. The upper chip obtained in (3-1) above is subjected to conditions of 100 ° C., 2.94 N / chip, and 1 second through the adhesive layer on the surface of the diced silicon wafer chip coated with the polyimide resin. And bonded. Then, the temperature was raised from room temperature at a temperature rising rate of 3 ° C./minute, heated at 125 ° C. for 1 hour, further heated at a temperature rising rate of 3 ° C./minute, heated at 175 ° C. for 120 minutes, and bonded. The agent layer was cured to obtain a test piece.

  The obtained test piece was left to stand in an environment of 85 ° C. and 85% RH for 48 hours to absorb moisture. IR reflow was performed 3 times for the test piece for measurement after moisture absorption at a maximum temperature of 260 ° C. and a heating time of 1 minute. After IR reflow, a pressure cooker test was further performed for 168 hours under the conditions of 121 ° C., 2.2 atm, and 100% RH. In this way, a test specimen for measurement subjected to the heat and humidity treatment was obtained. IR reflow was performed using a reflow furnace (WL-15-20DNX type) manufactured by Sagami Riko Co., Ltd.

(3-3) Measurement of shear strength The test specimen for measurement obtained in the above (3-2) was left on a measurement stage of a bond tester set at 250 ° C. for 30 seconds. After standing, stress was applied in the horizontal direction (shear direction) to the adhesive layer interface at a speed of 500 μm / s from a position 100 μm higher than the bonding interface (adhesive layer interface). The force (shear strength. The unit was N) was measured when the adhesion state of the measurement specimen was broken. In addition, about six test specimens, each shear strength was measured and the average value was made into shear strength. In addition, as a bond tester, Bond Tester Series 4000 manufactured by Dage was used.

[4. (Evaluation of surface mountability)
(4-1) Production of upper chip A dry polishing process was performed on the surface of the silicon wafer by a wafer backside grinding apparatus (DGP 8760, manufactured by DISCO Corporation). The adhesive sheet was affixed to a dry polished surface of a silicon wafer (200 mm diameter, 75 μm thick) using a tape mounter (manufactured by Lintec Corporation, Adwill RAD-2500 m / 8) and fixed to the ring frame. . Then, the ultraviolet-ray was irradiated from the base-material surface side of the said adhesive sheet using the ultraviolet irradiation device (The Lintec Co., Ltd. product, Adwill RAD-2000). The ultraviolet irradiation conditions were 350 mW / cm ² and 190 mJ / cm ² .
Next, the silicon wafer was diced into chips having a size of 8 mm × 8 mm using a dicing apparatus (manufactured by DISCO Corporation, DFD651). The amount of cut at the time of dicing was cut at a depth of 20 μm from the chip side with respect to the base material of the adhesive sheet. After dicing, the chip was picked up from the substrate together with the adhesive layer of the adhesive sheet to obtain an upper chip.

(4-2) Production of Lower Chip Using the wafer backside grinding apparatus (DGP 8760, manufactured by DISCO Corporation), the dry polishing treatment is performed on the surface of the silicon wafer in the same manner as the production of the upper chip in (4-1). gave. A dicing die bonding sheet (Lintech Co., Ltd., LE4738) is used on a dry polished surface of a silicon wafer (200 mm diameter, 75 μm thick) using a tape mounter (Lintech Co., Ltd., Adwill RAD-2500 m / 8). And fixed to the ring frame. Then, the ultraviolet-ray was irradiated from the base-material surface side of the said adhesive sheet using the ultraviolet irradiation device (The Lintec Co., Ltd. product, Adwill RAD-2000). The ultraviolet irradiation conditions were 350 mW / cm ² and 190 mJ / cm ² .
Next, the silicon wafer was diced into chips having a size of 8 mm × 8 mm using a dicing apparatus (manufactured by DISCO Corporation, DFD651). The amount of cut at the time of dicing was cut at a depth of 20 μm from the chip side with respect to the base material of the dicing die bonding sheet. After dicing, the chip was picked up from the substrate together with the adhesive layer of the dicing die bonding sheet to obtain a lower chip.

(4-3) Manufacturing of semiconductor package As a wiring board for die-bonding a chip, a two-layer double-sided board having a circuit pattern formed on a copper foil of a copper foil-clad laminate and having a solder resist on the pattern was used. . Specifically, the copper foil-clad laminate is BT resin CCL-HL832HS manufactured by Mitsubishi Gas Chemical Co., Ltd., and the solder resist is PSR-4000 AUS303 manufactured by Taiyo Ink Manufacturing Co., Ltd. As the substrate, LNTEG0001 (size: 157 mm × 70 mm × 0.22 t, maximum unevenness 15 μm) manufactured by Nippon CMK Co., Ltd. was used. In order to remove moisture, the two-layer double-sided substrate was allowed to stand in an atmosphere of 125 ° C. for 20 hours and dried.

  The lower chip obtained by picking up in the above (4-2) was placed on the dried double-sided double-sided substrate so that the adhesive layer was interposed between the double-sided double-sided substrate and the chip. After mounting, the lower chip was die-bonded to the two-layer double-sided substrate under the conditions of 125 ° C., 2.45 N / chip and 0.5 second. After die bonding, the temperature is raised from room temperature at a temperature rising rate of 3 ° C./min, heated at 120 ° C. for 30 minutes, further heated at a temperature rising rate of 3 ° C./min, heated at 140 ° C. for 30 minutes, and bonded. The agent layer was sufficiently heated and cured.

  Next, the upper chip obtained by picking up in the above (4-1) was further die-bonded on the lower chip on which the adhesive layer was cured by die-bonding on the two-layer double-sided substrate. At this time, the upper chip was die-bonded so that the adhesive layer was interposed between the lower chip and the upper chip. The die bonding was performed under the conditions of 125 ° C., 2.45 N / chip, and 0.5 second. After die bonding, the temperature was raised from room temperature at a rate of temperature rise of 3 ° C./min and heated at 125 ° C. for 1 hour to heat and cure the adhesive layer of the upper chip.

  Thereafter, the two-layer double-sided substrate on which the upper chip and the lower chip were mounted was sealed with a mold resin so that the sealing thickness was 400 μm. Sealing was performed by transfer molding using a sealing device under the conditions of 180 ° C., resin injection pressure of 6.9 MPa, and 120 seconds. Thereafter, the mold resin was sufficiently cured under conditions of 175 ° C. and 5 hours under normal pressure. As mold resin, KE-G1250 made by Kyocera Chemical Co., Ltd. was used. As a sealing device, MPC-06M Trial Press manufactured by Apic Yamada Corporation was used.

  Next, the two-layer double-sided substrate thus sealed is affixed to a dicing tape (manufactured by Lintec Co., Ltd., Adwill D-510T), and a dicing apparatus (manufactured by Disco Co., Ltd., DFD651) is used. A semiconductor package for surface mountability evaluation was obtained by dicing to a size of 25 mm.

(4-4) Evaluation of surface mountability of semiconductor package The obtained semiconductor package was left to stand for 168 hours under conditions of 85 ° C. and 85% RH to absorb moisture. The semiconductor package after moisture absorption was subjected to IR reflow three times under the conditions of a maximum temperature of 260 ° C. and a heating time of 1 minute. IR reflow was performed using a reflow furnace (WL-15-20DNX type) manufactured by Sagami Riko Co., Ltd.
About the semiconductor package after IR reflow, the presence or absence of peeling of the joint portion between the upper chip and the lower chip and the presence or absence of generation of a package crack were evaluated by a scanning ultrasonic flaw detector and cross-sectional observation. When peeling of an area of 5.0 mm ² or more was observed at the joint between the upper chip and the lower chip, it was determined that peeling occurred. Further, when a crack having an area of 5.0 mm ² or more was observed in the sealing resin portion on the outer periphery of the chip bonding portion, it was determined that a package crack had occurred. As a scanning ultrasonic flaw detector, Hye-Focus manufactured by Hitachi Construction Machinery Finetech Co., Ltd. was used.
The number of evaluated semiconductor packages was 25. The number of non-defective products was determined by counting the number of semiconductor packages in which no peeling or package cracking occurred.

[5. Preparation of adhesive composition]
The compounds used for the preparation of the adhesive compositions according to Examples and Comparative Examples are shown below.

(5-1) Acrylic polymer (A)
(A1) Methyl acrylate homopolymer (Mw = 310,000, Tg = 10 ° C.)
(A2) Methyl acrylate / 2-hydroxyethyl acrylate random polymer
Copolymer composition molar ratio:
Methyl acrylate / 2-hydroxyethyl acrylate = 85/15
(Mw = 300,000, Tg = 6 ° C.)
(A3) Methyl acrylate / 2-hydroxyethyl acrylate random polymer
Copolymer composition molar ratio:
Methyl acrylate / 2-hydroxyethyl acrylate = 95/5
(Mw = 750,000, Tg = 9 ° C., Mw / Mn = 4.2)
(A4) Methyl acrylate / 2-hydroxyethyl acrylate random polymer
Copolymer composition molar ratio:
Methyl acrylate / 2-hydroxyethyl acrylate = 95/5
(Mw = 700,000, Tg = 9 ° C., Mw / Mn = 1.8)
(A5) Methyl acrylate / benzyl acrylate random polymer
Copolymer composition molar ratio:
Methyl acrylate / benzyl acrylate = 95/5
(Mw = 300,000, Tg = 10 ° C.)
(A6) Methyl acrylate / glycidyl methacrylate random polymer
Copolymer composition molar ratio:
Methyl acrylate / glycidyl methacrylate = 85/15
(Mw = 300,000, Tg = 14 ° C.)

(5-2) Epoxy thermosetting resin (B)
(B1) Liquid epoxy resin:
Bisphenol A type epoxy resin containing 20% by weight acrylic particles
Epoxy equivalent 235 g / eq, viscosity = 1500 mPa · s (23 ° C.)
(B2) Solid epoxy resin:
Cresol novolac epoxy resin
Epoxy equivalent of 213 to 223 g / eq, softening point of 90 to 94 ° C.,
Viscosity = 3000 mPa · s (150 ° C)
(B3) Solid epoxy resin: polyfunctional epoxy resin
Epoxy equivalent of 158 to 178 g / eq, softening point of 60 to 72 ° C.,
Viscosity = 210 mPa · s (150 ° C.)
(B4) Solid epoxy resin: DCPD type epoxy resin
Epoxy equivalent 265-300 g / eq, softening point 75-90 ° C.,
Viscosity = 800 mPa · s (150 ° C)

(5-3) Thermosetting agent (C)
(C) Novolac type phenolic resin
Phenolic hydroxyl group equivalent 104 g / eq, softening point 111 ° C.,
Viscosity = 3030 mPa · s (150 ° C)

(5-4) Silane compound (D)
(D) Silane coupling agent compound:
(Poly-3- (2,3-epoxypropoxy) propylmethoxysiloxane, and a copolymer of polydimethoxysiloxane (methoxy equivalent 13.7 to 13.8 mmol / g, molecular weight 2000 to 3000) and polymethoxysiloxane (methoxy equivalent) 20.8 mmol / g, molecular weight 600)

(5-5) Curing accelerator (E)
(E) Curing accelerator: 2-phenyl-4,5-di (hydroxymethyl) imidazole

(5-6) Energy beam polymerizable compound (F)
(F) Energy beam polymerizable compound: dicyclopentadiene dimethoxydiacrylate

(5-7) Photopolymerization initiator (G)
(G) Photopolymerization initiator: α-hydroxycyclohexyl phenyl ketone

(5-8) Inorganic filler (H)
(H) Inorganic filler: SiO ₂ filler

(5-9) Other components (I)
(I) Other components: Thermoplastic polyester resin (Mw = 3000, Tg = 53 ° C., viscosity = 600 mPa · s (200 ° C.))

  Table 1 shows the compositions of the adhesive compositions prepared in Examples 1 to 3 and Comparative Examples 1 to 4. In Table 1, the value of the compounding amount of each compound indicates a mass part in terms of solid content. In this specification, solid content means all components other than a solvent.

  The adhesive compositions according to Examples and Comparative Examples described in Table 1 were diluted with methyl ethyl ketone so that the solid content concentration was 50% by mass. The diluted adhesive composition was applied onto a silicone-treated release film (SP-PET 381031 manufactured by Lintec Corporation) to form a coating film. After the application, the coating film was dried by heating in an oven at 100 ° C. for 2 minutes to form an adhesive layer having a thickness of about 40 μm. Then, the adhesive layer and the polyethylene film (thickness 100 μm, surface tension 33 mN / m) as a base material were bonded together, and the adhesive layer was transferred onto the base material to obtain an adhesive sheet. The above-described various tests were performed using the obtained adhesive sheet.

  About the hardened | cured material of the adhesive composition which concerns on an Example and a comparative example, it observed with the scanning probe microscope. The obtained surface phase image of the 125 μm × 125 μm region is shown in FIG. 1, and the surface phase image of the 20 μm × 20 μm region is shown in FIG. FIG. 3 shows a Fourier transform image obtained by performing two-dimensional fast Fourier transform (2D-FFT) on the surface phase image.

FIG. 4 shows a one-dimensional intensity distribution profile and background obtained based on the Fourier transform image (FIG. 3A) according to the first embodiment, and FIG. 5 shows a corrected state according to the first embodiment. The profile is shown. As shown in FIG. 5, the corrected profile shows the first peak at the position of wave number q ₂ = 0.80 [μm ⁻¹ ], and wave number q ₁ = 5.7 [μm ⁻¹ ]. A second peak was shown at the position. For Examples 2 to 3 and Comparative Examples 1 to 4, similarly to Example 1, wave numbers indicating the first peak and the second peak were obtained from the profile after correction.

  Using the adhesive sheets according to Examples and Comparative Examples, the adhesive composition was evaluated by the above-described method. The evaluation results are shown in Table 2.

As shown in Table 2, the adhesive compositions of Examples 1 to 3 has a structure periodicity that satisfy the relationship of the correlation length L ₁ and L ₂ described above in the cured product, the High adhesiveness was shown compared with the adhesive composition which concerns on Comparative Examples 1-4 which does not have structural periodicity. Specifically, it is as follows. In the tensile strength test, the adhesive compositions according to Examples 1 to 3 exhibited higher tensile strength than Comparative Examples 1 to 4 in both low speed and high speed conditions. In the shear strength test, the adhesive compositions according to Examples 1 to 3 showed higher shear strength than Comparative Examples 1 to 4. Moreover, the adhesive composition which concerns on Examples 1-3 showed the high adhesive force with respect to a to-be-adhered body, when passing through the heat-humidity conditions and reflow process in a semiconductor manufacturing process.

  The present invention can be used for an adhesive composition and an adhesive sheet.

Claims (4)

An adhesive composition comprising an acrylic polymer, an epoxy thermosetting resin, and a thermosetting agent,
The cured product obtained by curing the adhesive composition has a phase separation structure,
The phase-separated structure of the cured product, the first correlation length L _1, and the adhesive composition characterized by having a 6.5μm or more second correlation length L ₂ following 1.2 [mu] m. The adhesive composition according to claim 1,
The first correlation length L ₁ is calculated by the following mathematical formula (Equation 1), and the second correlation length L ₂ is calculated by the following mathematical formula (Equation 2).
L ₁ = 2π / q ₁ ≦ 1.2 μm (Equation 1)
L ₂ = 2π / q ₂ ≧ 6.5 μm (Expression 2)
(In the mathematical formula (Equation 1), q ₁ observes the surface phase image of the cured product using a scanning probe microscope, and performs a two-dimensional fast Fourier transform on the surface phase image to obtain a Fourier transform image. And obtaining a one-dimensional intensity distribution profile indicating the relationship of the intensity to the wave number based on the Fourier transform image, and the wave number indicating the first peak in the one-dimensional intensity distribution profile (unit: μm ⁻¹ ). ,
In the mathematical formula (Equation 2), q ₂ is a wave number (unit: μm ⁻¹ ) indicating the second peak in a wave number region lower than the first peak. ) In the adhesive composition according to claim 1 or 2,
Furthermore, the adhesive composition characterized by including a silane compound. An adhesive layer comprising the adhesive composition according to any one of claims 1 to 3,
And an adhesive sheet.