JP5233066B2 - Adhesive sheet for electronic materials - Google Patents

Description

  The present invention relates to an adhesive sheet for electronic materials. More specifically, the present invention relates to an adhesive sheet that constitutes a substrate for connecting a semiconductor integrated circuit used when various electronic materials, particularly, a semiconductor integrated circuit is mounted and packaged.

  In recent years, with the advancement of electronic technology, there has been an increasing demand for electronic information terminals to be reduced in size, weight, and functionality. In semiconductor integrated circuit (IC) packages, BGA, LGA, PGA, and the like have been put to practical use as means for increasing the number of pins and reducing the size. Above all, the BGA system is a package excellent in increasing the number of pins, reducing the weight, and reducing the thickness.

  FIG. 1 shows an example of the BGA method. In order to connect the IC 1, it has an insulating layer 3, a wiring substrate layer composed of a conductor pattern 5 and an adhesive layer 4, a gold bump 2, and a solder resist 7. As connection portions, solder balls 8 that substantially correspond to the number of pins of the IC are provided in a grid (grid array). Further, the IC is sealed with the sealing resin sheet 6. A TAB (Tape Automated Bonding) tape or a flexible printed circuit board is often used as a wiring board layer composed of an insulator layer and a conductor pattern.

  In such an IC package, characteristics required for the sealing resin sheet and the adhesive include (a) easy processability, (b) reflow resistance, and (c) a conductor pattern in a low temperature-high temperature cycle. Examples include stress relaxation (thermal cycle resistance) generated between members such as an IC and an insulator layer, and (d) insulation.

  Among them, reflow resistance and thermal cycle resistance are important. When reflow resistance is low, interfacial delamination between components in mounting methods where the entire IC package is heated to a high temperature, such as solder bath immersion, heating with a saturated vapor of an inert gas (paper phase method), or infrared reflow. This reduces the reliability of the IC package. This is thought to be due to the fact that the water absorbed in the member explosively vaporizes and expands during heating, and the water vapor generated during reflow cannot enter the sealing resin sheet or adhesive. It is required to be hard and have high adhesive strength at high temperatures. In particular, in recent years, lead-free solder used for connecting external terminals has been promoted as an effort to reduce environmentally hazardous substances. Lead-free solder has a higher melting point than conventional lead-based solder, and therefore the reflow temperature is about 30 ° C. higher than that of conventional lead-based solder, which is 250 to 260 ° C. Accordingly, high reflow resistance is also required for members constituting the IC package.

  Thermal cycle resistance is one of the important high temperature reliability. Of the components of the IC package, the linear expansion coefficient of the IC is about 5 ppm / ° C., the wiring board layer is 20-30 ppm / ° C. when the polyimide film base is used, and the conductor pattern is 14-18 ppm / ° C. when the conductor pattern is copper foil. It is. The temperature of the IC package is at a room temperature level when the operation is stopped, but exceeds 100 ° C. due to heat generated by the IC during driving. Therefore, the IC package is exposed to a low temperature-high temperature cycle, and stress is generated between the members due to the difference in linear expansion coefficient. Therefore, the resin sheet or adhesive that seals them is required to relieve the stress generated during this temperature cycle.

  In addition, even in a multilayer wiring board on which elements such as ICs and electronic parts are mounted, it is caused by a difference in linear expansion coefficient between the IC and the multilayer wiring board or between the conductor layer and the insulator layer in the multilayer wiring board. The stress relaxation property against the thermal history is important, and the above-described thermal cycle resistance is required.

So far, many adhesives composed of acrylonitrile-butadiene copolymer, acrylic rubber, epoxy resin, curing agent and the like have been proposed in terms of excellent adhesion, reflow resistance, and electrical characteristics. In particular, an adhesive composition using acrylic rubber or the like has been proposed as an adhesive having excellent thermal cycle resistance (see, for example, Patent Documents 1 and 2).
JP-A-3-181580 (pages 1 to 4) JP 2001-49221 A (paragraphs [0008] to [0027])

  In recent years, with regard to electronic materials such as semiconductor devices and wiring boards, higher density and higher current have been increasingly advanced. In such high-density, large-current compatible ICs and in-vehicle applications that are exposed to high use environment temperatures, there is a demand for reliability at 150 ° C. or higher, and in some cases 175 ° C. The known adhesive composition has a problem that, under such a high temperature condition, the metal of the conductor pattern or the active surface of the IC is oxidized and corroded by oxygen at a high temperature condition, causing problems such as interface peeling and defective circuit insulation. .

  Therefore, an object of the present invention is to solve the problems of conventional adhesive compositions and to provide an adhesive sheet for electronic materials that is excellent in thermal cycle resistance and insulation reliability.

That is, the present invention has at least one gas barrier layer and at least one adhesive layer containing a thermoplastic resin and a thermosetting resin, and at least one of the gas barrier layers has a glass transition point of 200 ° C. or higher. The adhesive sheet for electronic materials is characterized by having an oxygen permeability of 1.0 × 10 ⁻¹³ mol / m ² · s · Pa or less.

  ADVANTAGE OF THE INVENTION According to this invention, the adhesive sheet for electronic materials excellent in thermal cycle resistance and insulation reliability can be obtained.

  The adhesive sheet for electronic materials (hereinafter referred to as an adhesive sheet) in the present invention is a sealing resin sheet for sealing a semiconductor element, a heat dissipation plate or a reinforcing plate in a semiconductor package, and an interlayer between a wiring board (interposer) It is an adhesive sheet used for an adhesive, an interlayer adhesive of a multilayer wiring board, a sealing resin sheet for sealing a component mounted on a circuit board, and the shape and material of the adherend are not particularly limited.

The adhesive sheet of the present invention has an oxygen permeability of 1.0 × 10 ⁻¹³ mol / m ² · s · Pa or less. When the oxygen permeability exceeds 1.0 × 10 ⁻¹³ mol / m ² · s · Pa, defects such as peeling due to high-temperature oxidation occur on the metal of the conductor pattern and the active surface of the IC, resulting in poor thermal cycle resistance. . In addition, the insulation reliability of the circuit pattern decreases due to oxidative corrosion.

  The oxygen permeability can be measured, for example, using a gas permeability measuring device (equipment name, MT-C3) manufactured by Toyo Seiki Seisakusho. The oxygen permeability in the present invention refers to a value at a temperature of 25 ° C. and a relative humidity of 0%.

The adhesive sheet of the present invention comprises at least one gas barrier layer and at least one adhesive layer in order to have an oxygen permeability of 1.0 × 10 ⁻¹³ mol / m ² · s · Pa or less. that Yusuke. By having the gas barrier layer, the oxygen permeability can be reduced, and the thermal cycle resistance and the insulation reliability can be improved. The gas barrier layer may be in the inner layer or the surface layer of the adhesive sheet. When the gas barrier layer is included in the inner layer, for example, the gas barrier layer is formed on the adhesive layer, and then the adhesive layer is laminated thereon. A plurality of gas barrier layers may be formed by repeating this procedure a plurality of times. When a plurality of gas barrier layers are formed, two or more gas barrier layers may be combined. Further, the types of the adhesive layers to be laminated are not limited to the same type, and two or more different adhesive layers may be combined. Or after forming a gas barrier layer on an organic insulating film, it is also possible to laminate | stack an adhesive bond layer on the one or both surfaces of the organic insulating film.

  It is preferable that at least one of the gas barrier layers is made of at least one selected from the group consisting of an inorganic oxide, an inorganic nitride, an inorganic oxynitride, and a metal because oxygen permeability can be reduced.

  In addition, at least one of the gas barrier layers is preferably a layer having low oxygen permeability and excellent heat resistance. Materials that form layers with low oxygen permeability and excellent heat resistance include polyimide films, aramid films, aliphatic polyamide films, polyphenylene sulfide films, polyetherimide films, polyethersulfone films, polyarylate films, polyethylene naphthalates. Examples include phthalate films and polyethylene terephthalate films.

From the viewpoint of heat resistance, a film glass transition point of 200 ° C. or higher, a polyimide film, aramid film, polyetherimide film, polyether sulfone film, and the like. In addition, from the viewpoint of oxygen permeability, a film having an oxygen permeability of 1.0 × 10 −13 mol / m 2 · s · Pa or less is more preferable, and an aramid film or the like is exemplified. The film may be a single layer or a laminated film, and may be the same type or different types.

  The glass transition point of the gas barrier layer can be measured using a dynamic viscoelasticity measuring apparatus (for example, DMS6100 manufactured by Seiko Instruments Inc.). The glass transition point in the present invention refers to a value measured in a tensile mode at a frequency of 1 Hz, a heating rate of 5 ° C./min, and a temperature measurement range of −70 to 400 ° C. In the present invention, a glass transition point of 200 ° C. or higher is defined to include those having no glass transition point in this measurement temperature range.

  In the present invention, the film thickness of the gas barrier layer is not particularly limited as long as it can achieve the oxygen permeability of the adhesive sheet for electronic materials of the present invention, and is set as appropriate, but the gas barrier layer may be an inorganic oxide, an inorganic nitride, When it consists of at least 1 type chosen from the group which consists of an inorganic oxynitride and a metal, it is preferable that the film thickness is 5-5000 nm. If the film thickness is 5 nm or more, the gas barrier effect is high, and if it is 5000 nm or less, the flexibility as an adhesive sheet is not impaired and it is suitable for adhesion to an adherend. The film thickness can be adjusted by the transport speed when the gas barrier layer is continuously formed by roll-to-roll. It can also be adjusted by adjusting the amount of source gas, oxygen gas, etc. supplied when forming the gas barrier layer.

  Moreover, when a gas barrier layer is a film, it is preferable that a film thickness is 100 micrometers or less. If it is 100 micrometers or less, the flexibility as an adhesive sheet is not impaired, and it is suitable for adhesion | attachment to a to-be-adhered body.

  The adhesive composition constituting the adhesive layer of the adhesive sheet of the present invention is not particularly limited, but acrylonitrile-butadiene copolymer (NBR), styrene-ethylene-butadiene copolymer (SEBS), acrylonitrile-butadiene-styrene. Copolymer (ABS), acrylic rubber, polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, polyesterimide resin, polysulfone resin, polyethersulfone resin, polyphenylene sulfide resin, polyvinyl butyral resin, polyurethane resin, polyester resin Examples thereof include known resins such as silicone resin, phenoxy resin, polyurea resin, epoxy resin, phenol resin, melamine resin, xylene resin, furan resin, and cyanate ester resin.

Adhesiveness, heat resistance, from the viewpoint of insulation reliability, the adhesive layer of the present invention, a thermoplastic resin and a thermosetting resin, respectively, at least one including. The thermoplastic resin has functions such as adhesion, flexibility, relaxation of thermal stress, and improvement of insulation due to low water absorption. In addition, a thermosetting resin alone can form a hard but brittle adhesive film, but adding a thermoplastic resin to it adds toughness and provides an excellent adhesive.

  Although it does not specifically limit as a thermoplastic resin, From the point of adhesiveness, flexibility, and the relaxation effect of a thermal stress, NBR, SEBS, the acrylate ester which has a C1-C8 side chain, and / or Or a copolymer (acrylic rubber) containing methacrylic acid ester and acrylonitrile as a copolymerization component, polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, polyesterimide resin, polysulfone resin, polyethersulfone resin, polyphenylene sulfide resin Examples thereof include polyvinyl butyral resin, polyurethane resin, polyester resin, silicone resin, phenoxy resin, and polyurea resin. Further, one kind or plural kinds of thermoplastic resins may be used. These thermoplastic resins may have a functional group capable of reacting with a thermosetting resin described later. Specific examples include an amino group, a carboxyl group, an epoxy group, a hydroxyl group, a methylol group, an isocyanate group, a vinyl group, and a silanol group. These functional groups are preferable because the bond with the epoxy resin becomes strong and the heat resistance is improved.

  As the polyamide resin, those containing a dicarboxylic acid having 36 carbon atoms (so-called dimer acid) as an essential component are suitable. Polyamide resin containing dimer acid is obtained by polycondensation of dimer acid and diamine by a conventional method. At this time, dicarboxylic acid other than dimer acid, azelaic acid, sebacic acid and the like is contained as a copolymerization component. Also good. As the diamine, known ones such as ethylene diamine, hexamethylene diamine, and piperazine can be used, and two or more kinds may be mixed from the viewpoint of hygroscopicity and solubility.

  As a thermoplastic resin, from the balance of adhesiveness, heat resistance, chemical resistance, and the like, acrylonitrile-butadiene copolymer (NBR-C) having a carboxyl group, styrene-butadiene-ethylene resin (SEBS-C), An acrylic rubber having an epoxy group, a carboxyl group or a hydroxyl group can be mentioned. Here, “C” means having a carboxyl group.

  Examples of NBR-C include those obtained by carboxylating terminal groups of a copolymer rubber obtained by copolymerizing acrylonitrile and butadiene at a molar ratio of about 10/90 to 50/50, or acrylonitrile, butadiene and acrylic acid, maleic acid, etc. And terpolymer rubbers of carboxyl group-containing polymerizable monomers. Specifically, PNR-1H (manufactured by Nippon Synthetic Rubber Co., Ltd.), “Nipol” 1072J, “Nipol” DN612, “Nipol” DN631 (manufactured by Nippon Zeon Co., Ltd.), “Hiker” CTBN (BF Goodrich Etc.). Moreover, MX-073 (Asahi Kasei Co., Ltd. product) can be illustrated as SEBS-C.

  As the carboxyl group-containing acrylic rubber, SG-280DR, SG-70L, WS-023B (manufactured by Nagase ChemteX Corporation), and as the epoxy group-containing acrylic rubber, SG-P3, SG-80H (above Nagase Chemtex) XFP-1834 (manufactured by Toupe Co., Ltd.) and the like can be exemplified as “Nipol” AR-51 (manufactured by Nippon Zeon Co., Ltd.) and hydroxyl group-containing acrylic rubber.

  Among them, an acrylic rubber having an epoxy group, a carboxyl group, or a hydroxyl group is particularly preferably used because it does not contain a diene bond in the main chain and is not easily deteriorated by high temperature oxidation.

  The thermosetting resin is preferably used for realizing a balance of heat resistance, insulation at high temperature, chemical resistance, strength of the adhesive layer, and the like. Specific examples include known resins such as epoxy resins, phenol resins, melamine resins, xylene resins, furan resins, and cyanate ester resins. The epoxy resin is not particularly limited as long as it has two or more epoxy groups in one molecule, but diglycidyl ether such as bisphenol F, bisphenol A, bisphenol S, resorcinol, dihydroxynaphthalene, dicyclopentadiene diphenol, and epoxidation Examples include phenol novolak, epoxidized cresol novolak, epoxidized trisphenylol methane, epoxidized tetraphenylol ethane, epoxidized metaxylene diamine, cyclohexane epoxide, and the like. Specific examples include YD-128 (manufactured by Toto Kasei Co., Ltd.), “Epicoat” 828, “Epicoat” 1001, “Epicoat” 180 (manufactured by Japan Epoxy Resin Co., Ltd.), and the like. Furthermore, it is also effective to use a halogenated epoxy resin, particularly a brominated epoxy resin, for imparting flame retardancy. At this time, although the flame retardancy can be imparted only by the brominated epoxy resin, the heat resistance of the adhesive is greatly reduced, and therefore, it is more effective to use a mixed system with a non-brominated epoxy resin. Examples of brominated epoxy resins include copolymerized epoxy resins of tetrabromobisphenol A and bisphenol A, or brominated phenol novolac type epoxy resins such as “BREN” -S (manufactured by Nippon Kayaku Co., Ltd.). . Two or more kinds of these brominated epoxy resins may be mixed in consideration of bromine content and epoxy equivalent.

  As the phenol resin, any known phenol resin such as novolak type phenol resin and resol type phenol resin can be used. For example, alkyl-substituted phenols such as phenol, cresol, pt-butylphenol, nonylphenol, p-phenylphenol, cyclic alkyl-modified phenols such as terpene and dicyclopentadiene, hetero groups such as nitro groups, halogen groups, cyano groups, and amino groups Examples thereof include those having functional groups containing atoms, those having a skeleton such as naphthalene and anthracene, and resins composed of polyfunctional phenols such as bisphenol F, bisphenol A, bisphenol S, resorcinol, and pyrogallol.

  The total content of the thermosetting resin is preferably 5 to 400 parts by weight, more preferably 50 to 200 parts by weight with respect to 100 parts by weight of the thermoplastic resin. When the content is 5 parts by weight or more, an effect of improving the elastic modulus at high temperature is obtained, and the heat resistance of the adhesive sheet can be improved. When the content is 400 parts by weight or less, the flexibility of the adhesive sheet is maintained, and the stress relaxation effect and heat resistance are balanced, which is preferable.

  It is not limited at all that the adhesive layer constituting the adhesive sheet of the present invention contains a thermosetting resin curing agent and a curing accelerator. For example, triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol and 1,8-diazabicyclo (5,4,0) Tertiary amine compounds such as undecene-7, 3,3 ′, 5,5′-tetramethyl-4,4′-diaminodiphenylmethane, 3,3 ′, 5,5′-tetraethyl-4,4′-diaminodiphenylmethane 3,3′-dimethyl-5,5′-diethyl-4,4′-diaminodiphenylmethane, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 2,2′3,3′-tetrachloro- 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminobenzopheno 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzophenone, 3,4,4'-triaminodiphenyl sulfone, etc. Group polyamines, boron trifluoride amine complexes such as boron trifluoride triethylamine complex, imidazole derivatives such as 2-alkyl-4-methylimidazole and 2-phenyl-4-alkylimidazole, phthalic anhydride, trimellitic anhydride, etc. Organic phosphine compounds such as organic acid, dicyandiamide, triphenylphosphine, trimethylphosphine, triethylphosphine, tributylphosphine, tri (p-methylphenyl) phosphine and tri (nonylphenyl) phosphine can be used. These may be used alone or in combination of two or more. The content is preferably 0.1 to 50% by weight of the entire adhesive composition.

  Moreover, a silane coupling agent can also be used together as a hardening | curing agent. The silane coupling agent has an organic functional group capable of binding or binding to silicon with an organic matrix, and a hydrolyzable group capable of binding to an inorganic material. Examples of the organic functional group include an alkyl group, a phenyl group, an amino group, an epoxy group, a vinyl group, a methacryloxy group, a mercaptooxy group, and generally bonded to a silicon atom via an alkylene group having 1 to 6 carbon atoms. doing. Among them, those having an epoxy group or an amino group as organic functional groups are preferable because they have good reactivity and excellent reflow resistance of the adhesive. Specifically, when the organic functional group is an amino group, γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltris (β-methoxy-ethoxy-ethoxy) silane, N-methyl -Γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, triaminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-4,5-dihydroxyimidazolepropyltriethoxysilane and the like can be mentioned. When the organic functional group is an epoxy group, β-3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyl Examples include diethoxysilane.

  In addition to the above components, inorganic particles may be contained for the purpose of improving film strength and improving adhesive strength and heat resistance. The content of the inorganic particles is preferably 5 to 60% by weight of the entire adhesive composition. When it is 5% by weight or more, an effect of improving the film strength is obtained, and when it is 60% by weight or less, the effect of improving the film strength is high without impairing the adhesive strength.

  As for the kind of the inorganic particles, those that do not decompose at a temperature of 250 to 260 ° C. during solder reflow are particularly preferable from the viewpoint of reflow resistance. Specific examples include metal oxides such as silica, alumina, zirconium oxide, zinc oxide, antimony trioxide, antimony pentoxide, magnesium oxide, titanium oxide, iron oxide, cobalt oxide, chromium oxide, talc, aluminum, gold, silver Metal fine particles such as nickel and iron, carbon black, and glass. You may use these individually or in mixture of 2 or more types.

  Of these, silica is particularly preferable from the viewpoints of the thermal decomposition temperature greatly exceeding 300 ° C., the ease of adjusting the fluidity of the adhesive sheet, and the stability of the particle size. The particle shape and crystallinity are not particularly limited, and crushing systems, spheres, scales, etc. are used, but the dispersibility in the paint is good, the adhesive composition has excellent adhesive strength, film strength, etc., and the thermal expansion coefficient Since the effect of lowering is large, fused spherical silica is preferably used. The method for producing the fused silica does not necessarily need to go through a molten state, and examples thereof include a method of melting crystalline silica and a method of synthesizing from various raw materials.

  The particle size of the inorganic particles is not particularly limited, but the average particle size is preferably 0.01 to 2 μm from the viewpoints of dispersibility, coatability, reflow resistance, and the like. When the average particle size is 0.01 μm or more, it is possible to obtain a uniform dispersed state without causing particle aggregation in the adhesive coating during the adhesive manufacturing process, improving film strength, adhesive strength, and heat resistance. Can be improved. When the average particle size is 2 μm or less, the dispersion of the particles in the adhesive composition is good, the embedding failure in the adherend does not occur, and the effect of improving the film strength is excellent.

  The average particle size of the inorganic particles can be measured using a laser diffraction / scattering particle size distribution measuring device, a dynamic light scattering particle size distribution measuring device, or the like. Moreover, the particle diameter contained in an adhesive bond layer can also be investigated by TEM (transmission electron microscope) observation of the adhesive bond cross section after hardening.

  These inorganic particles may be subjected to surface treatment using a silane coupling agent or the like in order to improve heat resistance, adhesive strength and the like.

In the present invention, the thickness of the adhesive layer can be appropriately selected in relation to embedding in the unevenness of the adherend, adhesive strength, reflow resistance, thermal cycle resistance, etc., and is not particularly limited, but is preferably 10 to 500 μm. . Furthermore, the oxygen permeability can be easily ^adjusted to 1.0 × 10 ⁻¹³ mol / m ² · s · Pa or less, and the thermal cycle resistance and the embedding property of the adherend are excellent, 40-500 micrometers is more preferable.

  The adhesive sheet of the present invention may have a protective layer on one side or both sides in order to protect the adhesive layer. The material of the protective layer is not particularly limited as long as it does not impair the form and function of the adhesive sheet until the adhesive sheet is bonded to the adherend, and can be peeled off from the adhesive sheet as necessary. Specific examples thereof include polyester, polyolefin, polyphenylene sulfide, polyvinyl chloride, polytetrafluoroethylene, polyvinyl fluoride, polyvinyl butyral, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyamide, polyimide, polymethyl methacrylate and other plastic films, Films that have been coated with a release agent such as silicone, alkyd resin, polyolefin resin, or fluorine-containing compound, or paper laminated with these films, a laminate of these films, or a resin having releasability Examples thereof include paper impregnated or coated. Moreover, a sand mat processed film is also mentioned. This is one in which fine irregularities are formed by spraying fine particles on the film surface, and the releasability can be adjusted by the irregularity level. Among these, a film which has been subjected to a release treatment such as silicone or a fluorine-containing compound that can be easily adjusted for releasability is preferably used. More preferably, the polyester film subjected to the above-described mold release treatment is excellent in terms of heat resistance.

  When it has a protective layer, it is preferable that the adhesive force of a protective layer and an adhesive bond layer is 1-200 N / m, More preferably, it is 3-150 N / m. If it is 1 N / m or more, the protective layer does not fall off and is suitable for processing. If it is 200 N / m or less, it can peel as needed at the time of actual use of an adhesive sheet, and is suitable. In particular, when protective films are provided on both sides of the adhesive sheet, F1-F2 is preferably 5 N / m or more when the peel strength of each protective film from the adhesive layer is F1, F2 (F1> F2). More preferably, it is 10 N / m or more. The peeling force is measured at a peeling angle of 90 ° and a peeling speed of 300 mm / min.

  The protective layer may be colored with a pigment or the like so as to have good visibility during processing. For example, when there are protective layers on both sides of the adhesive sheet, if a colored film is used only for the protective film on the side to be peeled first, the film to be peeled can be easily recognized, so that misuse can be avoided.

  Further, the adhesive sheet of the present invention has an adhesive agent for preventing the entrapment of air bubbles when pasting to an adherend such as an IC, a conductor pattern or an insulator layer when the sheet surface layer is an adhesive layer. One side or both sides of the sheet may be roughened to reduce the adhesiveness of the adhesive sheet. The tackiness referred to here is stickiness of the surface of the adhesive sheet. When the adhesiveness is high, it becomes easy to bite bubbles when the adhesive sheet is stuck on the adherend. Once bubbled, there is no escape route and remains as a residual bubble, which may adversely affect the subsequent reliability. According to this method, the adhesiveness is reduced by dispersing the contacts to the adherend. The method for roughening the adhesive is not particularly limited, but the following examples can be given.

  When a coating liquid in which the adhesive composition is dissolved is applied onto a film and dried to produce a semi-cured adhesive sheet, if the surface shape of the film to which the adhesive composition is applied is uneven, Unevenness can be transferred to the surface of the adhesive sheet and roughened. For example, any film that has been embossed or sand-matted may be used. Moreover, if a film with unevenness is used for the protective layer of the produced adhesive sheet and the film is laminated, the unevenness is similarly transferred to the surface of the adhesive sheet. However, since the adhesive is embedded in the unevenness of the film surface, it may be difficult to peel off the film in actual use. For this reason, the film preferably used in the present invention is a film which has been subjected to mold release treatment such as silicone or a fluorine-containing compound. In addition, the adhesive sheet can be roughened with an uneven rubber roll or the like.

  Moreover, it can also be set as a low-adhesion adhesive sheet by combining the technique which lowers | hangs adhesiveness by thinly laminating | stacking a low-adhesive adhesive layer on the adhesive sheet of this invention, and roughening. Specific examples of the low-tack adhesive layer include an adhesive layer in which the amount of inorganic particles is increased, or an adhesive layer whose adhesiveness is controlled by performing heat aging on a thin adhesive sheet.

  Next, an example of a method for manufacturing the adhesive sheet of the present invention and an IC package in which IC sealing is performed using the adhesive sheet will be described.

  (1) Production of an adhesive sheet for electronic materials: An adhesive solution obtained by dissolving an adhesive composition in a solvent is applied on a polyester film (protective film A) subjected to a release treatment, and then semi-cured by drying. That is, an adhesive layer in a B stage state is obtained. It is preferable to apply so that the thickness of the adhesive layer is 10 to 100 μm. The drying conditions are usually 100 to 200 ° C. and 1 to 5 minutes. Solvents are not particularly limited, but aromatics such as toluene, xylene and chlorobenzene, ketones such as methyl ethyl ketone and methyl ethyl isobutyl ketone (MIBK), aprotic such as dimethylformamide (DMF), dimethylacetamide and N-methylpyrodoline A polar system solvent alone or a mixture is preferred.

  On the coated and dried adhesive layer, a polyester or polyolefin-based protective film (protective film B) having higher releasability is laminated while being wound on a roll, and an adhesive sheet in a B-stage state (semi-cured) Hereinafter, it is referred to as an adhesive sheet A). In some cases, after the lamination, for example, the degree of curing may be adjusted by aging at 40 to 100 ° C. for about 1 to 200 hours. Next, while peeling off the protective film B of the obtained adhesive sheet A, a gas barrier layer is formed on the adhesive surface by the method described above. The adhesive sheet thus obtained (hereinafter referred to as adhesive sheet B) has the structure shown in FIG.

  Next, using the adhesive solution used previously, it is applied onto the protective film B and dried to obtain an adhesive layer in a B-stage state. An adhesive sheet having a laminated structure in which the protective film A / adhesive layer / gas barrier layer / adhesive layer / protective film B is obtained by winding the roll onto the roll while laminating the gas barrier layer surface of the adhesive sheet B previously produced thereon. (Hereinafter referred to as the adhesive sheet C). FIG. 3 shows the structure of the adhesive sheet C.

  (2) Fabrication of semiconductor integrated circuit connection substrate (patterned TAB tape): A TAB tape having a three-layer structure in which an adhesive layer and a protective film layer are laminated on a polyimide film is formed in the following (a) to (d). Process by process. (A) Sprocket and device hole drilling, (b) Thermal lamination with copper foil, (c) Pattern production by copper foil etching, (d) Tin or gold plating treatment. As described above, a patterned TAB tape is obtained.

  (3) Fabrication of semiconductor device: The inner lead portion of the patterned TAB tape obtained in (2) is thermocompression-bonded (inner lead bonding) to a gold bump of the IC, and the IC is mounted. Next, the adhesive sheet C obtained in (1) is pressure-bonded to the IC sealing portion with a vacuum pressure bonding machine or the like. After the pressure bonding, finally, post-curing is performed at 80 to 200 ° C. for about 15 to 180 minutes in order to heat and cure the adhesive sheet C in a hot air oven. Thus, a semiconductor device is obtained. FIG. 1 is a cross-sectional view of one embodiment of a semiconductor device.

  In particular, in an IC package having a large number of pins, a metal plate for the purpose of reinforcement, heat dissipation, and electromagnetic shielding, a so-called stiffener or heat spreader may be laminated on the TAB tape, and the structure as shown in FIG. take. In order to connect the IC 1, it has an insulating layer 3, a wiring board layer composed of a conductor pattern 5 and an adhesive layer 4, gold bumps 2, solder resists 7, and solder balls 8. Further, the IC is sealed with the sealing resin sheet 6. Further, a stiffener is bonded to the insulator layer 3 by the adhesive sheet 13. The adhesive sheet of the present invention can be used for the sealing resin sheet 6 and the adhesive sheet 13 of FIG. In particular, the use of the adhesive sheet for electronic materials of the present invention for adhering a stiffener or a heat spreader to a TAB tape is preferable from the viewpoints of adhesion, reflow resistance, and thermal cycle resistance.

  The adhesive sheet of the present invention can also be used as an interlayer adhesive for multilayer wiring boards, has low oxygen permeability, and can prevent oxidation of the copper foil in the multilayer wiring board, and thus has excellent insulation reliability. Show properties. An example of a method for manufacturing a multilayer wiring board is shown below.

  (1) The adhesive sheet for electronic materials of the present invention is temporarily bonded by a laminator to at least one surface of a film substrate having a conductor pattern on at least one surface. Further, with the conductor layer of the film substrate having a conductor layer on one side facing outside, the film is heat-pressed onto the above adhesive sheet, post-cured, and laminated and integrated.

  (2) After the via hole is formed by performing laser processing on at least one side of the laminated substrate obtained in the step (1), electroless plating and electrolytic plating are performed, conductive treatment is performed, and the layers are electrically connected.

  (3) The conductor layer of the multilayer substrate obtained in the step (2) is processed into a predetermined pattern by etching. By sequentially performing the above steps, a multilayer wiring board having an arbitrary number of layers can be obtained.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited at all by these Examples. First, evaluation methods used in Reference Examples, Examples and Comparative Examples will be described.

<1> Preparation of evaluation pattern tape An 18 μm thick electrolytic copper foil was applied to a tape with adhesive for TAB (trade name # 7100, manufactured by Toray Industries, Inc.) at 140 ° C., 0.3 MPa, 0.3 m / min. And roll laminated. Subsequently, in an air oven, a heat curing treatment was sequentially performed at 80 ° C. for 3 hours, at 100 ° C. for 5 hours, and at 150 ° C. for 5 hours to prepare a TAB tape with copper foil. An evaluation pattern having a comb-shaped conductor pattern with a conductor width of 25 μm and a conductor distance of 25 μm is formed by forming a photoresist film on the copper foil surface of the obtained TAB tape with copper foil by a conventional method, etching and resist peeling. A tape was prepared.

<2> Adhesive Strength The adhesive sheet of the present invention was roll-laminated on the conductor pattern of the evaluation pattern tape prepared in the above <1> under the conditions of 130 ° C., 0.5 MPa, and 0.3 m / min. Thereafter, in the air oven, a post-cure was sequentially performed at 100 ° C. for 1 hour and at 160 ° C. for 2 hours to prepare an evaluation sample. After slitting to a width of 5 mm from the adhesive sheet side, the adhesive sheet was peeled off at a speed of 50 mm / min in the 90 ° direction, and the adhesive strength at that time was measured. The adhesive strength is preferably 5 N / cm or more from the viewpoint of processability, handling properties, and device reliability.

<3> Reflow resistance 20 pieces prepared by cutting the post-cured evaluation sample prepared by the method <2> into 30 mm squares were prepared. The sample was heat-dried at 125 ° C. for 12 hours and then moisture-absorbed for 168 hours under conditions of 30 ° C. and 70% RH, and then subjected to IR reflow at a maximum temperature of 250 ° C. for 10 seconds or a maximum temperature of 260 ° C. for 10 seconds. The peeled state was observed with an ultrasonic short wound machine. In the test at each reflow temperature, the number of samples where peeling occurred in 20 pieces was examined, and the ratio was defined as a defective rate.

<4> Oxygen permeability The adhesive sheet from which the protective layer was peeled was sequentially post-cured in an air oven at 100 ° C. for 1 hour and 160 ° C. for 2 hours. The post-cured sample was measured for oxygen permeability at a temperature of 25 ° C. and a relative humidity of 0% in accordance with the JIS K7126 A method. As a measuring device, a gas permeability measuring device (equipment name, MT-C3) manufactured by Toyo Seiki Seisakusho Co., Ltd. was used.

<5> Thermal cycle test Twenty pieces of post-cured evaluation samples prepared by the method of <2> were cut into 30 mm squares. The sample was put into a thermal cycle tester (PL-3 type, manufactured by Tabai Espec Co., Ltd.), and a thermal cycle test was performed at -65 ° C to 175 ° C. The cycle of holding the minimum temperature and the maximum temperature for 30 minutes each was evaluated for the presence or absence of delamination in the sample after a total of 500 cycles. The number of samples where peeling occurred in 20 pieces was examined, and the ratio was defined as the defective rate.

<6> High-temperature, high-humidity insulation reliability Using a post-cured evaluation sample prepared by the method of <2> above, in a thermo-hygrostat (Tabba Espec Co., Ltd., TPC-211D type), 130 ° C. The resistance value was measured in a state where a voltage of 100 V was continuously applied under the condition of 85% RH, and the time required to reach 1 × 10 ⁻⁸ or less was measured. The measurement was performed up to 500 hours.

<7> High-Temperature Insulation Reliability Using the post-cured evaluation sample prepared by the method <2> above, the resistance value is measured in a state where a voltage of 100 V is continuously applied in a 175 ° C. oven. The time required to become × 10 ⁻⁸ or less was measured. The measurement was performed up to 250 hours.

Reference Example 1 (Synthesis of polyamide resin)
Dimer acid PRIPOL 1009 (manufactured by Unikema) and adipic acid as the acid, hexamethylenediamine as the amine, an acid / amine ratio in an equal amount, an acid / amine reactant, 1% or less phosphoric acid catalyst, The mixture was stirred and heated at 1 ° C. for 1 hour and at 205 ° C. for 1.5 hours. Under a vacuum of 2 kPa, the mixture was held for 0.5 hours and allowed to cool to obtain a polyamide resin having a weight average molecular weight of 20000 and an acid value of 10.

Reference Examples 1-6
The following thermoplastic resins, epoxy resins and other additives are blended so as to have the composition ratios shown in Table 1, respectively, and DMF (dimethylformamide) / monochlorobenzene / MIBK (methyl ethyl isobutyl) to a concentration of 28% by weight. Ketone) An equal amount of mixed solvent was stirred and dissolved at 40 ° C. to prepare an adhesive solution.

A. Thermoplastic resin NBR-C (made by Nippon Zeon Co., Ltd., trade name Nipol 1072)
Epoxy group-containing acrylic rubber (manufactured by Nagase ChemteX Corporation, trade name SG-P3)
Carboxyl group-containing acrylic rubber (manufactured by Nagase ChemteX Corporation, trade name SG-70L)
Polyamide resin produced in Reference Example B. Epoxy resin o-cresol novolac type epoxy resin (product name: Epicoat 180, manufactured by Japan Epoxy Resin Co., Ltd.)
Bisphenol A type epoxy resin (product name: Epicoat 828, manufactured by Japan Epoxy Resin Co., Ltd.)
Novolac brominated epoxy resin (Nippon Kayaku Co., Ltd., trade name BREN-S)
C. Inorganic particle spherical silica (manufactured by Tokuyama Corporation, trade name SE-1, average particle size 0.7 μm)
Spherical silica (manufactured by Admatechs, trade name SO-C1, average particle size 0.2 μm)
Aluminum hydroxide (made by Showa Denko KK, trade name Hijilite 43M, average particle size 0.6 μm)
D. Phenol resinPhenol novolak resin (Gunei Chemical Industry Co., Ltd., trade name PSM4261)
Alkylphenol resin (manufactured by Hitachi Chemical Co., Ltd., trade name: Hitanol 2410)
E. Additive 4,4′-diaminodiphenylsulfone γ-aminopropyltriethoxysilane 2-undecylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name Curezol C11Z)
Imidazolium trimellitate (manufactured by Shikoku Kasei Kogyo Co., Ltd., trade name: Curazole 2PZ-CNS).

  These adhesive solutions were applied to a 75 μm thick polyester film (trade name V2, hereinafter referred to as “polyester film 1”, manufactured by Nipper Co., Ltd.) having a surface treated with a silicon with a bar coater so as to have a dry thickness of 50 μm. Apply, dry at 100 ° C. for 1 minute and 150 ° C. for 5 minutes, and laminate a polyester film (made by Nipper Co., Ltd., trade name HSP, hereinafter referred to as polyester film 2) having a lower peel strength than polyester film 1 on it. While being wound on a roll, an adhesive sheet (hereinafter referred to as an adhesive sheet 1) having an adhesive layer having a B-stage (semi-cured) thickness of 50 μm was prepared. When the peel strength of the polyester film used here was measured by a peel test using a 31B tape of Nitto Denko Corporation, the polyester film 1 was 4 N / m and the polyester film 2 was 1.5 N / m. Next, while peeling the polyester film 2 of the adhesive sheet 1, a gas barrier layer made of silicon oxide having a thickness of 100 nm was formed on the adhesive layer using a sputtering method. The adhesive sheet thus obtained (hereinafter referred to as adhesive sheet 2) has the structure shown in FIG. Next, the adhesive solution used previously was applied on the polyester film 2 to a dry thickness of 50 μm and dried at 100 ° C. for 1 minute and 150 ° C. for 5 minutes. On top of that, the laminate is wound on a roll while laminating so that the gas barrier layer of the adhesive sheet 2 previously prepared is laminated, polyester film 1 / adhesive layer 50 μm / gas barrier layer 100 nm / adhesive layer 50 μm / polyester film 2 An adhesive sheet 3 having a laminated structure was prepared. The evaluation results of the obtained adhesive sheet 3 are shown in Table 1.

Reference examples 7 and 8
An aluminum oxide film having a thickness of 100 nm was formed as a gas barrier layer by a sputtering method, and an adhesive sheet was prepared in the same manner as in Reference Example 1 except that the adhesive composition shown in Table 2 was used. Table 2 shows the evaluation results of the obtained adhesive sheet.

Reference Example 9
An adhesive sheet was prepared in the same manner as in Reference Example 3, except that a 100 nm thick silicon oxide film was formed as a gas barrier layer by plasma CVD using hexamethyldisiloxane as the vapor deposition monomer gas. Table 2 shows the evaluation results of the obtained adhesive sheet.

Examples 1-3
An adhesive solution was prepared in the same manner as in Reference Example 1 except that the adhesive composition described in Table 2 was used. The adhesive solution was applied with a bar coater onto a 75 μm thick polyester film 1 whose surface was treated with silicone so as to have a dry thickness of 50 μm, and dried at 100 ° C. for 1 minute and 150 ° C. for 5 minutes. An aramid film (product name: Mikutron, glass transition point 270 ° C., film thickness 4 μm) manufactured by Toray Industries, Inc. is wound on a roll while laminating at a laminating roll temperature of 80 ° C. to form a B-stage (semi-cured) An adhesive sheet having an adhesive layer with a thickness of 50 μm (hereinafter referred to as an adhesive sheet 4) was produced. The adhesive sheet 4 thus obtained has the structure shown in FIG.

  Next, the adhesive solution used previously was applied on the polyester film 2 to a dry thickness of 50 μm and dried at 100 ° C. for 1 minute and 150 ° C. for 5 minutes. On top of that, the laminate sheet is wound at a laminating roll temperature of 80 ° C. so that the aramid film surface of the adhesive sheet 4 prepared above is laminated, and the polyester film 1 / adhesive layer 50 μm / aramid film / adhesive An adhesive sheet (hereinafter, referred to as an adhesive sheet 5) having a laminated structure to be an agent layer 50 μm / polyester film 2 was produced. The evaluation results of the obtained adhesive sheet 5 are shown in Table 2.

Example 4
An adhesive sheet was produced in the same manner as in Example 2 except that the aramid film was changed to a polyimide film (trade name Kapton 100H, film thickness 25 μm, manufactured by Toray DuPont Co., Ltd.). Table 3 shows the evaluation results of the obtained adhesive sheet.

  In addition, the inflection point of the elastic modulus change in the measurement with a dynamic viscoelasticity measuring apparatus was not seen in the polyimide film used in this example.

Comparative Example 1
An adhesive sheet was prepared in the same manner as in Example 2 except that the aramid film was replaced with a polyethylene naphthalate film (manufactured by Teijin DuPont Films, trade name: Teonex Q51, glass transition point 121 ° C., film thickness 25 μm). did. Table 3 shows the evaluation results of the obtained adhesive sheet.

Comparative Examples 2-4
Using the adhesive composition described in Table 3, an adhesive sheet having a laminated structure of polyester film 1 / adhesive layer 100 μm / polyester film 2 was prepared in the same manner as in Reference Example 1 except that no gas barrier layer was formed. . Table 3 shows the evaluation results of the obtained adhesive sheet.

As is apparent from the results of Reference Examples, Examples and Comparative Examples in Tables 1 to 3, an adhesive sheet for electronic materials excellent in thermal cycle resistance and insulation reliability can be obtained by the present invention.

Sectional drawing which shows the one aspect | mode of a BGA type semiconductor device. Sectional drawing which shows the one aspect | mode of the adhesive agent sheet for electronic materials of this invention. Sectional drawing which shows the one aspect | mode of the adhesive agent sheet for electronic materials of this invention. Sectional drawing which shows the one aspect | mode of the BGA type semiconductor device processed using the adhesive agent sheet for semiconductor devices of this invention.

Explanation of symbols

1 IC
2 Gold bump 3 Insulator layer 4 Adhesive layer 5 Conductor pattern 6 Sealing resin sheet 7 Solder resist 8 Solder ball
9 Gas Barrier Layer 10 Adhesive Layer 11 Protective Layer 12 Stiffener 13 Adhesive Sheet

Claims (2)

The film has at least one gas barrier layer and at least one adhesive layer containing a thermoplastic resin and a thermosetting resin, and at least one of the gas barrier layers has a glass transition point of 200 ° C. or higher. The adhesive sheet for electronic materials characterized by having an oxygen permeability of 1.0 × 10 ⁻¹³ mol / m ² · s · Pa or less. Protective layer / claim 1 Symbol mounting electronic materials adhesive sheet having a laminated structure of the adhesive layer / gas barrier layer / adhesive layer / protective layer.

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