JP2007314603A - Pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet, and method for manufacturing semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition which can achieve high packaging reliability even when it is exposed to severe reflow conditions in a packaging on which thin semiconductor chips are mounted. <P>SOLUTION: The pressure-sensitive adhesive composition comprises an acrylic copolymer (A), an epoxy-based thermosetting resin (B), a compound (C) having a functional group which can react with an epoxy group and an unsaturated hydrocarbon group in a molecule, and a photoinitiator (D). In particular, the functional group in the compound (C) is preferably a phenolic hydroxyl group. Further, the compound (C) is most preferably a phenolic resin containing a novolac-type unsaturated group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is particularly suitable for use in a step of die bonding a semiconductor element (semiconductor chip) to an organic substrate or a lead frame and a step of dicing a silicon wafer or the like and die bonding a semiconductor chip to an organic substrate or a lead frame. The present invention relates to an adhesive composition, an adhesive sheet having an adhesive layer composed of the adhesive composition, and a method for manufacturing a semiconductor device using the adhesive sheet.

  Semiconductor wafers such as silicon and gallium arsenide are manufactured in a large diameter state, and the wafer is cut and separated (diced) into element small pieces (IC chips) and then transferred to a mounting process which is the next process. At this time, the semiconductor wafer is subjected to dicing, cleaning, drying, expanding, and pick-up processes in a state where the semiconductor wafer is previously adhered to the adhesive sheet, and then transferred to the next bonding process.

  In order to simplify the processes of the pick-up process and the bonding process among these processes, various dicing / die bonding adhesive sheets having both a wafer fixing function and a die bonding function have been proposed (for example, Patent Documents 1 to 4).

  Patent Documents 1 to 4 disclose an adhesive sheet comprising an adhesive layer made of a specific composition and a substrate. This adhesive layer has a function of fixing the wafer at the time of wafer dicing. Further, since the adhesive force is reduced by irradiation with energy rays and the adhesive force between the substrate and the substrate can be controlled, When the pickup is performed, the adhesive layer is peeled off together with the chip. When the IC chip with the adhesive layer is placed on the substrate and heated, the thermosetting resin in the adhesive layer exhibits an adhesive force, and the adhesion between the IC chip and the substrate is completed.

  The pressure-sensitive adhesive sheet disclosed in the above patent document enables so-called direct die bonding, and the application step of the die bonding adhesive can be omitted. The adhesive agent disclosed in the above-mentioned patent document contains a low molecular weight energy ray curable compound as an energy ray curable component. By irradiation with energy rays, the energy ray-curable compound is polymerized and cured, the adhesive force is reduced, and the adhesive layer is easily peeled from the substrate. Moreover, after the die-bonding which passed energy beam hardening and thermosetting, all the components harden | cure the adhesive layer of said adhesive sheet, and a chip | tip and a board | substrate are adhere | attached firmly.

  In recent years, the required physical properties of semiconductor devices have become very strict. For example, package reliability in a severe hot and humid environment is required. However, as a result of thinning of the semiconductor chip itself, the strength of the chip is reduced, and it cannot be said that the package reliability in a severe heat and humidity environment is sufficient.

  In the adhesive disclosed in the above patent document, a low molecular weight energy ray curable compound is used as an energy ray curable component. Depending on the blending ratio, dispersion state, or curing condition, the shear strength is insufficient, and interface breakage is likely to occur in a hot and humid environment, and the adhesion between the chip and an adherend such as a printed wiring board is reduced. For this reason, semiconductor packages that are becoming stricter may not meet the required level in reliability.

In recent years, the surface mounting method used for connecting electronic components is a surface mounting method in which the entire package is exposed to a temperature higher than the melting point of the solder. Recently, due to environmental considerations, the mounting temperature has increased from 240 ° C to 260 ° C due to the shift to lead-free solder, increasing the stress generated inside the semiconductor package, further increasing the risk of package cracking. It has become.

That is, the reduction in the thickness of the semiconductor chip and the increase in the mounting temperature cause a decrease in the reliability of the package.
JP-A-2-32181 JP-A-8-239636 Japanese Patent Laid-Open No. 10-8001 JP 2000-17246 A

  For this reason, it is required to realize high package reliability even in a case where a package in which a semiconductor chip that is becoming thinner is mounted, even when exposed to severe reflow conditions.

  This invention is made | formed in view of the above prior arts, Comprising: It aims at meeting the said request | requirement by examining the adhesive agent used for die bonding.

The gist of the present invention aimed at solving such problems is as follows.
(1) Acrylic copolymer (A), epoxy thermosetting resin (B), compound (C) having a functional group capable of reacting with an epoxy group and an unsaturated hydrocarbon group in one molecule, and a photopolymerization initiator An adhesive composition comprising (D).
(2) The adhesive composition according to (1), wherein the functional group capable of reacting with the epoxy group is a phenolic hydroxyl group.
(3) The adhesive composition according to (1), wherein the compound (C) having a functional group capable of reacting with an epoxy group and an unsaturated hydrocarbon group in a molecule is a novolak type unsaturated group-containing phenol resin. object.
(4) An adhesive sheet in which an adhesive layer composed of the adhesive composition according to any one of (1) to (3) is formed on a substrate.
(5) A semiconductor wafer is attached to the adhesive layer of the adhesive sheet according to (4) above, the semiconductor wafer is diced into an IC chip, and an adhesive layer is provided on the back surface of the IC chip. It consists of a step of making the IC chip adhere to the die pad portion by thermocompression bonding through the adhesive layer after the semiconductor wafer is pasted and before the IC chip is peeled off. A manufacturing method of a semiconductor device including a step of irradiating an adhesive layer with energy rays in a stage.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can achieve high package reliability, even if it is a case where it is exposed to severe reflow conditions in the package which mounted the semiconductor chip which is thinning, and this adhesive An adhesive sheet having an adhesive layer made of the composition and a method for producing a semiconductor device using the adhesive sheet are provided.

Hereinafter, the present invention will be described more specifically.
The adhesive composition according to the present invention has in one molecule an acrylic copolymer (A), an epoxy thermosetting resin (B), a functional group capable of reacting with an epoxy group, and an unsaturated hydrocarbon group. The compound (C) (hereinafter referred to as “compound (C)”) and the photopolymerization initiator (D) are included as essential components, and other components may be included as necessary in order to improve various physical properties. Hereinafter, each of these components will be described in detail.

(A) Acrylic copolymer As an acrylic copolymer, a conventionally well-known acrylic copolymer is used. The weight average molecular weight of the acrylic copolymer is preferably from 10,000 to 2,000,000, and more preferably from 100,000 to 1,500,000. If the weight average molecular weight of the acrylic copolymer is too low, the adhesive strength with the base material becomes high and pickup failure may occur. If it exceeds 2 million, the adhesive layer may not follow the substrate irregularities. Causes voids and other factors. The glass transition temperature of the acrylic copolymer is preferably in the range of −10 ° C. to 50 ° C., more preferably 0 ° C. to 40 ° C., and particularly preferably 0 ° C. to 30 ° C. If the glass transition temperature is too low, the peeling force between the adhesive layer and the substrate may increase, resulting in chip pick-up failure. If it is too high, the adhesive force for fixing the wafer may be insufficient. There is. Moreover, as a monomer of this acrylic copolymer, a (meth) acrylic acid ester monomer or its derivative is mentioned. Examples include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, glycidyl methacrylate, glycidyl acrylate, and the like. Also, (meth) acrylic acid esters having a cyclic skeleton such as (meth) acrylic acid cycloalkyl ester, (meth) acrylic acid benzyl ester, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxy Ethyl acrylate, imide acrylate, (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms, such as (meth)
Examples include methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate. Vinyl acetate, acrylonitrile, styrene or the like may be copolymerized. In addition, it is preferable to have a hydroxyl group because the compatibility with the epoxy resin is good.

(B) Epoxy-type thermosetting resin As an epoxy-type thermosetting resin, conventionally well-known various epoxy resins are used. The epoxy resin is desirably contained in an amount of 1 to 1500 parts by weight, more preferably 3 to 1000 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). If the amount is less than 1 part by weight, sufficient adhesiveness may not be obtained. If the amount exceeds 1500 parts by weight, the peel strength from the substrate may be increased, resulting in pickup failure. Examples of the epoxy resin include bisphenol A diglycidyl ether and hydrogenated products thereof, orthocresol novolac epoxy resin (formula 1 below), dicyclopentadiene type epoxy resin (formula 2 below), biphenyl type epoxy resin or biphenyl compound ( Examples thereof include epoxy compounds having two or more functional groups in the molecule, such as the following formulas 3 and 4).
These can be used alone or in combination of two or more.

(Where n represents an integer of 0 or more)

(Where n represents an integer of 0 or more)

(Where n represents an integer of 0 or more)

(In the formula, R represents a hydrogen atom or a methyl group.)
(C) Compound having functional group capable of reacting with epoxy group and unsaturated hydrocarbon group in one molecule Compound (C) has both functional group capable of reacting with epoxy group and unsaturated hydrocarbon group in one molecule. If it is a thing, it will not specifically limit. The functional group capable of reacting with an epoxy group is preferably a phenolic hydroxyl group, an alcoholic hydroxyl group, an amino group, a carboxyl group and an acid anhydride, more preferably a phenolic hydroxyl group, an alcoholic hydroxyl group and an amino group, particularly preferably Is a phenolic hydroxyl group. Further, the unsaturated hydrocarbon group is not particularly limited as long as it has energy beam curability, and an ultraviolet curable one is more preferable. Specific examples include a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, an acrylamide group, and a methacrylamide group, and more preferably a methacryloyl group and an acrylamide group.

As such a compound (C), for example, a compound obtained by substituting a part of the hydroxyl group of a phenol resin with a group containing an unsaturated hydrocarbon group, or an aromatic ring of the phenol resin contains an unsaturated hydrocarbon group. Examples include compounds in which groups are directly bonded. Here, examples of the phenol resin include a phenol resin (described later) optionally used as a curing agent, and a novolak type phenol resin is particularly preferable. Therefore, the compound (C) includes a compound obtained by substituting a part of the hydroxyl group of the novolak type phenol resin with a group containing an unsaturated hydrocarbon group, or an aromatic group of the novolac type phenol resin with an unsaturated hydrocarbon group. A compound in which a group containing is directly bonded is preferable.

  Particularly preferred examples of such a compound (C) include a repeating unit containing a phenolic hydroxyl group such as the following formula (a) and an unsaturated hydrocarbon group such as the following formula (b) or (c). Examples thereof include compounds containing a repeating unit having a containing group.

(Wherein n is 0 or 1)

(In the formula, n is 0 or 1, R ¹ is an optionally substituted hydrocarbon group having 1 to 5 carbon atoms, X is —O—, —NR ² — (R ² is hydrogen or Methyl) or R ¹ X is a single bond and A is an acryloyl group or a methacryloyl group)
The number average molecular weight of the compound (C) is preferably 300 to 30000, more preferably 400 to 10000, and particularly preferably 500 to 3000. The proportion of the repeating unit represented by the formula (a) in the compound is 5 to 95 mol%, more preferably 20 to 90 mol%, particularly preferably 40 to 80 mol%, ) Or (c) The proportion of repeating units represented by the formula is 5 to 95 mol% in total, more preferably 10 to 80 mol%, and particularly preferably 20 to 60 mol%.

The phenolic hydroxyl group represented by the repeating unit (a) is a functional group capable of reacting with an epoxy group, and serves as a curing agent that reacts and cures with the epoxy group of the epoxy resin (B) when the adhesive is thermally cured. It has a function. In addition, the unsaturated hydrocarbon group represented by the repeating units (b) and (c) is polymerized and cured at the time of energy ray curing of the adhesive, and decreases the adhesive force between the adhesive layer and the substrate. Have the effect of Moreover, the unsaturated hydrocarbon group represented by the repeating units (b) and (c) improves the compatibility between the acrylic copolymer (A) and the epoxy thermosetting resin (B). As a result, the cured product of the adhesive becomes tougher, which improves the reliability as an adhesive.
(D) Photopolymerization initiator When the adhesive composition of the present invention is used, it may be irradiated with energy rays such as ultraviolet rays to reduce the adhesive force. At this time, by adding the photopolymerization initiator (D) to the composition, the polymerization curing time and the amount of light irradiation can be reduced.

  Specific examples of such a photopolymerization initiator 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, Examples include 2,4-diethylthioxanthone, a-hydroxycyclohexyl phenyl ketone, benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, dibenzyl, diacetyl, b-chloranthraquinone, and the like. A photoinitiator (D) can be used individually by 1 type or in combination of 2 or more types.

The blending ratio of the photopolymerization initiator (D) is theoretically determined based on the unsaturated bond amount present in the adhesive and its reactivity and the reactivity of the photopolymerization initiator used. Should be, but not always easy in complex mixture systems. As a general guideline, the photopolymerization initiator (D) is desirably contained in an amount of 0.1 to 10 parts by weight, more preferably 1 to 5 parts by weight, based on 100 parts by weight of the acrylic copolymer (A). If the amount is less than 0.1 parts by weight, satisfactory pick-up property may not be obtained due to insufficient photopolymerization. If the amount exceeds 10 parts by weight, a residue that does not contribute to photopolymerization is generated, and the curability of the adhesive is reduced. It may be insufficient.

The adhesive composition according to the present invention contains the acrylic copolymer (A), the epoxy thermosetting resin (B), the compound (C) and the photopolymerization initiator (D) as essential components, and various kinds In order to improve physical properties, the following components may be included as necessary.
(E) Curing Agent The curing agent (E) functions as a curing agent for the epoxy thermosetting resin (B) together with the compound (C). Whereas only the compound (C) is used, the curing agent (E) can be used to adjust the speed of the curing reaction and adjust the physical properties such as the elastic modulus of the cured product of the adhesive to a preferable region. . Preferred curing agents include compounds having two or more functional groups capable of reacting with an epoxy group in one molecule, and the functional groups include phenolic hydroxyl groups, alcoholic hydroxyl groups, amino groups, carboxyl groups, and acid anhydrides. Etc. Of these, phenolic hydroxyl groups, amino groups, acid anhydrides and the like are preferable, and phenolic hydroxyl groups and amino groups are more preferable. Specific examples thereof include novolak-type phenol resins represented by the following formula (Chemical Formula 7), dicyclopentadiene-based phenol resins represented by (Chemical Formula 8), polyfunctional phenol resins represented by (Chemical Formula 9), and the like. Phenolic curing agents and amine-based curing agents such as DICY (dicyandiamide). These curing agents can be used alone or in admixture of two or more.

  The amount of the compound (C) and the curing agent (E) used is 0.1 to 500 parts by weight in total of (C) + (E) with respect to 100 parts by weight of the epoxy thermosetting resin (B). It is preferably 1 to 100 parts by weight. In addition, the ratio (weight ratio) of compound (C) / curing agent (E) is preferably 0.5 or more, more preferably 1 or more, and particularly preferably 2 or more. The compound (C) may be used alone without using the curing agent (E).

  If the total amount of the compound (C) and the curing agent (E) is small, the adhesiveness may not be obtained due to insufficient curing, and if it is excessive, the moisture absorption rate may increase and the reliability of the package may be lowered. Moreover, if the compound (C) / curing agent (E) is small, the effects of the present invention may not be sufficiently obtained.

(Where n represents an integer of 0 or more)

(Where n represents an integer of 0 or more)

(Where n represents an integer of 0 or more)
(F) Curing accelerator The curing accelerator (F) is used to adjust the curing speed of the adhesive composition. Preferred curing accelerators include compounds that can promote the reaction between an epoxy group and a phenolic hydroxyl group or an amine. Specifically, triethylenediamine, benzyldimethylamine, triethanolamine, dimethylaminoethanol, tris ( Tertiary amines such as (dimethylaminomethyl) phenol, imidazoles such as 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, organic phosphines such as tributylphosphine, diphenylphosphine, triphenylphosphine, And tetraphenylboron salts such as tetraphenylphosphonium tetraphenylborate and triphenylphosphinetetraphenylborate. These can be used alone or in admixture of two or more.

It is preferable that 0.01-100 weight part is contained with respect to 100 weight part of epoxy-type thermosetting resins (B), and, as for a hardening accelerator (F), 0.1-50 weight part is more preferable, and 1-30. Part by weight is more preferred.
(G) Coupling agent A coupling agent is used in order to improve the adhesiveness and adhesiveness with respect to the to-be-adhered body of an adhesive composition. Moreover, the water resistance can be improved by using a coupling agent, without impairing the heat resistance of the hardened | cured material obtained by hardening | curing an adhesive composition. As the coupling agent, a compound having a group that reacts with a functional group of the above component (A), component (C), component (E), or the like is preferably used. As the coupling agent, a silane coupling agent is desirable. Such coupling agents include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ- (methacrylopropyl). ) 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, methyltrimethoxy Silane, methylto Examples include reethoxysilane, vinyltrimethoxysilane, vinyltriacetoxysilane, and imidazolesilane. These can be used alone or in admixture of two or more. When these coupling agents are used, they are usually used in a proportion of 0.1 to 20 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the epoxy resin. If it is less than 0.1 parts by weight, the effect cannot be obtained, and if it exceeds 10 parts by weight, it may cause outgassing.
(H) Crosslinking agent In order to adjust the initial adhesive force and cohesive force of the adhesive composition, a crosslinking agent may be added. Examples of the crosslinking agent include organic polyvalent isocyanate compounds and organic polyvalent imine compounds.

Examples of the organic polyvalent isocyanate compounds include aromatic polyvalent isocyanate compounds, aliphatic polyvalent isocyanate compounds, alicyclic polyvalent isocyanate compounds, trimers of these polyvalent isocyanate compounds, Examples thereof include terminal isocyanate urethane prepolymers obtained by reacting a polyvalent isocyanate compound and a polyol compound. Specific examples of the organic polyvalent isocyanate compound include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylene diisocyanate. Narate, diphenylmethane-4,4′-diisocyanate, diphenylmethane-2,4′-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4 ′ -Diisocyanate, dicyclohexylmethane-
2,4'-diisocyanate, lysine isocyanate and the like.

Specific examples of the organic polyvalent imine compound include N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane-tri-b-aziridinylpropionate, tetramethylol. Examples thereof include methane-tri-b-aziridinylpropionate, N, N′-toluene-2,4-bis (1-aziridinecarboxamide) triethylenemelamine, and the like.

The ratio of the crosslinking agent (H) is usually 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). Used in
(I) Inorganic filler By blending an inorganic filler into an adhesive, the thermal expansion coefficient can be adjusted, and the heat of the adhesive layer after curing with respect to a semiconductor chip, metal or organic substrate The heat resistance of the package can be improved by optimizing the expansion coefficient. It is also possible to reduce the moisture absorption rate after curing of the adhesive layer. Preferred inorganic fillers include powders such as silica, alumina, talc, calcium carbonate, titanium white, bengara, silicon carbide, boron nitride,
Examples thereof include beads formed by spheroidizing, single crystal fibers, and glass fibers. These can be used alone or in admixture of two or more. In the present invention, among these, the use of silica powder and alumina powder is preferable.

The inorganic filler can be adjusted in the range of usually 0 to 80% by weight with respect to the entire adhesive.
(J) Energy ray polymerizable compound The energy ray polymerizable compound (J) may be blended in the adhesive layer. Since the adhesive force of the adhesive layer can be reduced by curing the energy beam polymerizable compound (J) together with the compound (C) by energy ray irradiation, the interlayer between the base material and the adhesive layer Peeling can be easily performed.

  The energy beam polymerizable compound (J) is a compound that is polymerized and cured when irradiated with energy rays such as ultraviolet rays and electron beams. Specific examples of the energy ray polymerizable compound include trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and 1,4-butylene glycol. Acrylate compounds such as diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, oligoester acrylate, urethane acrylate oligomer, epoxy-modified acrylate, polyether acrylate, and itaconic acid oligomer are used. Such a compound has at least one polymerizable double bond in the molecule, and usually has a weight average molecular weight of about 100 to 30,000, preferably about 300 to 10,000.

When the energy ray polymerizable compound (J) is used, it is usually 1 to 40 parts by weight, preferably 3 to 30 parts by weight, more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the acrylic copolymer (A). It is used in the ratio. If it exceeds 40 parts by weight, the adhesion to the organic substrate or the lead frame may be lowered.
(Other ingredients)
In addition to the above, various additives may be blended in the adhesive composition of the present invention as necessary. For example, a flexible component can be added to maintain the flexibility after curing. The flexible component is a component having flexibility at normal temperature and under heating, and a component that is not substantially cured by heating or energy ray irradiation is selected. The flexible component may be a polymer made of a thermoplastic resin or an elastomer, or may be a polymer graft component or a polymer block component. Moreover, the modified resin by which the flexible component was previously modified | denatured by the epoxy resin may be sufficient.

Furthermore, as various additives for the adhesive composition, a plasticizer, an antistatic agent, an antioxidant, a pigment, a dye, or the like may be used.
(Adhesive composition)
The adhesive composition composed of each component as described above has pressure-sensitive adhesiveness and heat-curing property, and has a function of temporarily holding various adherends in an uncured state. Finally, a cured product with high impact resistance can be obtained through thermal curing, and it has an excellent balance between shear strength and peel strength, and can maintain sufficient adhesive properties even under severe heat and humidity conditions. .

The adhesive composition according to the present invention can be obtained by mixing the above components at an appropriate ratio. In mixing, each component may be diluted with a solvent in advance, or a solvent may be added during mixing.
(Adhesive sheet)
The adhesive sheet according to the present invention is obtained by laminating an adhesive layer made of the above adhesive composition on a substrate. The adhesive sheet according to the present invention can have any shape such as a tape shape or a label shape.

  As the base material of the adhesive sheet, for example, 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 A transparent film such as a polyimide film is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. In addition to the transparent film, an opaque film or a fluororesin film colored with these can be used. However, since the adhesive sheet of the present invention may be irradiated with energy rays such as ultraviolet rays from the substrate surface side when used, the substrate is preferably transparent to the energy rays to be used.

The adhesive sheet according to the present invention is affixed to various adherends, and after subjecting the adherend to the necessary processing, the adhesive layer remains adhered to the adherend and peels off from the substrate. Is done. That is, it is used for a process including a step of transferring an adhesive layer from a substrate to an 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.
It is desirable that it is mN / m 2 or less, particularly preferably 35 mN / m 2 or less. 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.

  As the release agent used for the substrate release treatment, alkyd, silicone, fluorine, unsaturated polyester, polyolefin, wax, etc. are used, and in particular, alkyd, silicone, fluorine release agents. Is preferable because it has heat resistance. In particular, an alkyd resin is preferable because of its high adhesion to the base film and easy adjustment of the surface tension.

  In order to release the surface of the substrate using the above release agent, the release agent can be applied directly with a gravure coater, Mayer bar coater, air knife coater, roll coater, etc. without solvent, or with solvent dilution or emulsion. The laminate may be formed by normal temperature or heating or electron beam curing, wet lamination, dry lamination, hot melt lamination, melt extrusion lamination, coextrusion processing, or the like.

The film thickness of the substrate is usually about 10 to 500 μm, preferably about 15 to 300 μm, and particularly preferably about 20 to 250 μm.
Moreover, the thickness of an adhesive agent layer is 1-500 micrometers normally, Preferably it is 5-300 micrometers, Most preferably, it is about 10-150 micrometers.

  The method for producing the adhesive sheet is not particularly limited, and may be produced by applying and drying a composition constituting the adhesive layer on the substrate, and the adhesive layer is peeled off. You may manufacture by providing on a film and transferring this to the said base material. In addition, before using an adhesive sheet, in order to protect an adhesive layer, you may laminate | stack a peeling film on the upper surface of an adhesive layer. Moreover, in order to fix other jigs, such as a ring frame, the adhesive layer and the adhesive tape may be separately provided in the surface outer peripheral part of the adhesive agent layer.

Next, a method of using the adhesive sheet according to the present invention will be described taking as an example the case where the adhesive sheet is applied to the manufacture of a semiconductor device.
In the method for manufacturing a semiconductor device according to the present invention, first, the adhesive sheet according to the present invention is fixed on a dicing apparatus by a ring frame, and one surface of the silicon wafer is bonded to the adhesive sheet. Place on the layer and press lightly to secure the wafer. Thereafter, the adhesive layer is irradiated with energy rays from the substrate side, the cohesive force of the adhesive layer is increased, and the adhesive force between the adhesive layer and the substrate is lowered. As energy rays to be irradiated, ultraviolet rays (UV) or electron beams (EB) are used, and preferably ultraviolet rays are used.

  Next, the silicon wafer is cut using a cutting means such as a dicing saw to obtain an IC chip. The cutting depth at this time is set to a depth that takes into account the total thickness of the silicon wafer and the adhesive layer and the amount of wear of the dicing saw.

  The energy beam irradiation may be performed at any stage after the semiconductor wafer is pasted and before the IC chip is peeled off. For example, it may be performed after dicing, or may be performed after the following expanding step. Further, the energy beam irradiation may be performed in a plurality of times.

  Then, if necessary, when the adhesive sheet is expanded, the IC chip interval is expanded, and the IC chip can be picked up more easily. At this time, a deviation occurs between the adhesive layer and the base material, the adhesive force between the adhesive layer and the base material is reduced, and the pick-up property of the chip is improved.

When the IC chip is picked up in this way, the cut adhesive layer can be adhered to the back surface of the IC chip and peeled off from the substrate.
Next, the IC chip is placed on the die pad portion through the adhesive layer. The die pad part is heated before placing the IC chip or immediately after placing. The heating temperature is usually 80 to 200 ° C., preferably 100 to 180 ° C., the heating time is usually 0.1 seconds to 5 minutes, preferably 0.5 seconds to 3 minutes, and the chip mount pressure is Usually, it is 1 kPa to 200 MPa.

  After the IC chip is chip-mounted on the die pad portion, further heating may be performed as necessary. The heating conditions at this time are in the above heating temperature range, and the heating time is usually 1 to 180 minutes, preferably 10 to 120 minutes.

  Through such a process, the adhesive layer is cured and the IC chip and the die pad part can be firmly bonded. Since the adhesive layer is fluidized under die-bonding conditions, the adhesive layer is sufficiently embedded in the unevenness of the die pad portion, and generation of voids can be prevented.

  That is, in the obtained mounting product, since the adhesive which is a fixing means of the chip is cured and is sufficiently embedded in the unevenness of the die pad portion, it is sufficient even under severe conditions. Package reliability and board mountability are achieved.

  In addition, the adhesive composition and adhesive sheet of this invention can be used for adhesion | attachment of a semiconductor compound, glass, ceramics, a metal other than the above usage methods.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive composition which can achieve high package reliability, and this adhesive composition even if it is a case where it is exposed to severe reflow conditions in the package which mounted the semiconductor chip which is thinning An adhesive sheet having an adhesive layer made of a product and a method for manufacturing a semiconductor device using the adhesive sheet are provided.

(Example)
EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

In the following examples and comparative examples, “evaluation of surface mountability” was performed as follows.
"Evaluation of surface mountability"
(1) Manufacture of semiconductor chip A tape mounter (Adwill RAD2500, manufactured by Lintec Corporation) affixed adhesive sheets of Examples and Comparative Examples to the polished surface of a # 2000 polished silicon wafer (150 mm diameter, 150 μm thick) And fixed to a ring frame for wafer dicing. After that, ultraviolet rays are irradiated from the substrate surface using an ultraviolet irradiation device (Adwill RAD2000, manufactured by Lintec Corporation) (350 mW / cm ² , 190 mJ / cm ² )
did. Next, the wafer was diced into a chip size of 8 mm × 8 mm using a dicing machine (Tokyo Seimitsu Co., Ltd., AWD-4000B). The amount of cut during dicing was such that the substrate was cut by 20 μm.
(2) Manufacture of semiconductor packages A circuit pattern is formed on the copper foil of a copper foil-clad laminate (CCL-HL830 manufactured by Mitsubishi Gas Chemical Co., Ltd.) as a substrate, and a solder resist (PSR4000 AUS5 made by Taiyo Ink) is 40 μm thick on the pattern The BT substrate possessed by the company was used (manufactured by Chino Giken Co., Ltd.). The chip on the adhesive sheet obtained in (1) above is picked up from the base material together with the adhesive layer, and pressed onto the BT substrate through the adhesive layer under the conditions of 120 ° C, 100gf, 1 second. did. Then, it is sealed with a mold resin (KE-1100AS3 manufactured by Kyocera Chemical Co., Ltd.) so that the sealing thickness is 400 μm (sealing device MPC-06M Trial Press manufactured by Apic Yamada Co., Ltd.), and the resin is cured at 175 ° C for 5 hours. It was. Next, the sealed BT substrate is affixed to dicing tape (Adwill D-510T manufactured by Lintec Corporation), and dicing is performed using a dicing machine (Tokyo Seimitsu Co., Ltd., AWD-4000B) to 12mm x 12mm size. A semiconductor package for reliability evaluation was obtained.
(3) Evaluation of semiconductor package surface mountability The obtained semiconductor package was allowed to stand for 168 hours at 85 ° C and 60% RH, and after moisture absorption, IR reflow with a maximum temperature of 260 ° C and heating time of 1 minute (reflow oven: Scanning ultrasonic flaw detector (Hye-Focus, manufactured by Hitachi Construction Machinery Finetech Co., Ltd.) for the presence or absence of floating / peeling of joints and occurrence of package cracks when performing Sagami Riko WL-15-20DNX) three times ) And cross-sectional observation.
The case where peeling of 0.5 mm or more was observed at the substrate / semiconductor chip junction was judged as peeling, and 25 packages were put into the test, and the number of pieces where peeling did not occur was counted.

Moreover, each component which comprises an adhesive composition is as follows.
(A) Acrylic copolymer: Coponil N-4617 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.
(B) Liquid epoxy resin: bisphenol A type epoxy resin (Epicoat 828 manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 189 g / eq)
(C) Novolac-type unsaturated group-containing phenol resin (Showon High Polymer Co., Ltd. Shounol ARS-046, molecular weight 2060, phenolic hydroxyl group equivalent 215 g / eq)
(D) Photopolymerization initiator (Irgacure 184, manufactured by Ciba Specialty Chemicals Co., Ltd.)
(E) Curing agent: Novolac type phenolic resin (Showa Polymer Co., Ltd .: Shonor BRG-556, phenolic hydroxyl group equivalent 104g / eq)
(F) Curing accelerator: Imidazole (Curesol 2PHZ manufactured by Shikoku Chemicals Co., Ltd.)
(G) Silane coupling agent (MKC silicate MSEP2 manufactured by Mitsubishi Chemical Corporation)
(H) Cross-linking agent: aromatic polyisocyanate (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.)
(I) Inorganic filler: Silica (Admafine SC2050 manufactured by Admatechs Co., Ltd.)
(J) Energy ray polymerizable compound: Dipentaerythritol hexaacrylate (Nippon Kayaku Co., Ltd. Karayad DPHA)
Further, a polyethylene film (thickness: 100 μm, surface tension: 33 mN / m) was used as the base material of the adhesive sheet.
(Examples and Comparative Examples)
The adhesive composition having the composition described in Table 1 was used. In the table, the numerical values indicate parts by weight in terms of solid content. The adhesive composition having the composition shown in Table 1 was applied on a silicone-treated release film (SP-PET3811 (S) manufactured by Lintec Corporation) so that the film thickness after drying was 30 μm, and dried (dried) After bonding in a condition oven at 100 ° C. for 1 minute, the substrate was bonded to the substrate, and the adhesive layer was transferred onto the substrate to obtain an adhesive sheet.

  Using the resulting adhesive sheet, surface mountability was evaluated. The results are shown in Table 2.

Claims (5)

  Acrylic copolymer (A), epoxy thermosetting resin (B), compound (C) having functional group capable of reacting with epoxy group and unsaturated hydrocarbon group in one molecule, and photopolymerization initiator (D) An adhesive composition comprising:   The adhesive composition according to claim 1, wherein the functional group capable of reacting with the epoxy group is a phenolic hydroxyl group.   The pressure-sensitive adhesive composition according to claim 1, wherein the compound (C) having a functional group capable of reacting with an epoxy group and an unsaturated hydrocarbon group in a molecule is a novolak type unsaturated group-containing phenol resin.   An adhesive sheet in which an adhesive layer comprising the adhesive composition according to any one of claims 1 to 3 is formed on a substrate. A semiconductor wafer is attached to the adhesive layer of the adhesive sheet according to claim 4, the semiconductor wafer is diced into an IC chip, and the adhesive layer is fixed and left on the back surface of the IC chip. It consists of a process of peeling from the substrate and thermocompression bonding the IC chip onto the die pad part via the adhesive layer, and sticking at any stage after the semiconductor wafer is pasted and before the IC chip is peeled off A method for manufacturing a semiconductor device, comprising a step of irradiating an adhesive layer with an energy beam.