JP2013127998A - Semiconductor device manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device manufacturing method which inhibits an occurrence of voids at an interface between a semiconductor element and an underfill sheet thereby to enable manufacturing of a highly reliable semiconductor device.SOLUTION: A manufacturing method of a semiconductor device including an attached body, a semiconductor element electrically connected to the attached body and an underfill material with which a space between the attached body and the semiconductor element is filled, comprises: a preparation step of preparing an encapsulation sheet including a dicing tape and an underfill material laminated on the dicing tape; a bonding step of bonding a circuit surface on which a connection member of a semiconductor wafer is formed and the underfill material of the encapsulation sheet under reduced pressure of not exceeding 1000 Pa; a dicing step of dicing the semiconductor wafer to form semiconductor elements with the underfill materials; and a connection step of electrically connecting the semiconductor element and the attached body via the connection member while filling a space between the attached body and the semiconductor element with the underfill material.

Description

  The present invention relates to a method for manufacturing a semiconductor device.

  In recent years, the demand for high-density packaging due to the miniaturization and thinning of electronic devices has increased rapidly. For this reason, the surface mount type suitable for high-density mounting is the mainstream of the semiconductor package instead of the conventional pin insertion type. In this surface mount type, the lead is soldered directly to a printed circuit board or the like. As a heating method, the entire package is heated and mounted by infrared reflow, vapor phase reflow, solder dipping, or the like.

  After the surface mounting, the space between the semiconductor element and the substrate is filled with a sealing resin in order to protect the surface of the semiconductor element and to ensure the connection reliability between the semiconductor element and the substrate. As such a sealing resin, although a liquid sealing resin is widely used, it is difficult to adjust the injection position and the injection amount with the liquid sealing resin. Therefore, a technique for filling a space between a semiconductor element and a substrate using a sheet-shaped sealing resin has also been proposed (Patent Document 1).

  In general, as a process using a sheet-shaped sealing resin (underfill sheet), after bonding an underfill sheet to a semiconductor wafer, the semiconductor wafer is diced to form a semiconductor element, and the semiconductor element is covered. A procedure is adopted in which a space between an adherend such as a substrate and the semiconductor element is filled with an underfill sheet integrated with the semiconductor element while being connected and mounted on the adherend. In the above process, the space between the adherend and the semiconductor element can be easily filled.

Patent No. 4438973

  On the other hand, the inventors of the present application have tried to develop a technology combining a dicing tape and an underfill sheet in order to improve the efficiency of a series of processes from dicing a semiconductor wafer to filling a space between a semiconductor element and an adherend. Yes. In this technique, since the circuit surface of the semiconductor wafer and the underfill sheet are bonded together, the underfill sheet is required to adhere to the undersurface of the semiconductor wafer following the irregularities. However, as the number of three-dimensional structures such as bumps on the semiconductor wafer increases and the circuit becomes narrower, the degree of adhesion of the underfill sheet to the semiconductor wafer decreases, and voids (bubbles) are formed between the semiconductor wafer and the underfill sheet. ) May occur. If air bubbles are present at the interface between the semiconductor wafer and the underfill material, the bubbles will expand and the adhesion between the semiconductor wafer and the underfill material will decrease when decompression or heat treatment is performed in the subsequent steps. As a result, the connection reliability between the semiconductor element and the adherend when the semiconductor element is mounted on the adherend is lowered. In addition, when moisture in the backside grinding or dicing of the semiconductor wafer is mixed in the bubbles, the heating process is performed after that, the moisture evaporates and the bubbles expand or expand. Connection reliability will be reduced.

  An object of the present invention is to provide a semiconductor device manufacturing method capable of suppressing the generation of voids at the interface between a semiconductor element and an underfill sheet and manufacturing a highly reliable semiconductor device.

  The inventors of the present application have conducted intensive studies and found that the object can be achieved by adopting the following configuration, and have completed the present invention.

That is, the present invention relates to a semiconductor device including an adherend, a semiconductor element electrically connected to the adherend, and an underfill material that fills a space between the adherend and the semiconductor element. A manufacturing method comprising:
Preparing a sealing sheet comprising a dicing tape and an underfill material laminated on the dicing tape; and
A bonding step of bonding the circuit surface on which the connecting member of the semiconductor wafer is formed and the underfill material of the sealing sheet under a reduced pressure of 1000 Pa or less;
A dicing step of dicing the semiconductor wafer to form the semiconductor element with the underfill material;
A connecting step of electrically connecting the semiconductor element and the adherend through the connecting member while filling a space between the adherend and the semiconductor element with the underfill material.

  In the manufacturing method, the circuit surface of the semiconductor wafer and the underfill material are bonded together under a reduced pressure of 1000 Pa or less, so that the gas inclusion at the interface between the two can be greatly reduced and the adhesion can be improved. As a result, the generation of voids at the interface can be suppressed. As a result, a semiconductor device having excellent connection reliability between the semiconductor wafer and the adherend can be efficiently manufactured. Moreover, since the dicing tape and the underfill material are integrated, the space between the semiconductor element and the adherend can be easily filled while firmly holding the semiconductor wafer or chip during dicing. Therefore, it is possible to efficiently carry out from dicing to filling at the time of electrical connection in the manufacture of the semiconductor device.

  In the manufacturing method, it is preferable that substantially no bubbles exist at the interface between the semiconductor wafer and the underfill material after the bonding step (hereinafter, sometimes simply referred to as “interface”). Thereby, since the adhesiveness between a semiconductor wafer and an underfill material improves, the connection reliability of a semiconductor device can be improved more. In the present specification, “substantially no bubbles” means a state in which no bubbles are visually confirmed when the pressure is reduced to a predetermined pressure for bonding in the bonding step, and the maximum diameter is 1 mm. It means that the above bubbles do not exist.

In the manufacturing method, the connecting step is a step of bringing the connecting member and the adherend into contact with each other under a temperature α of the following condition (1):
It is preferable to include a step of fixing the contact member in contact with the adherend at a temperature β of the following condition (2).
Condition (1): melting point of connecting member−100 ° C. ≦ α <melting point of connecting member Condition (2): melting point of connecting member ≦ β ≦ melting point of connecting member + 100 ° C.

  By adopting the connection step including the predetermined step, when the semiconductor element and the adherend are electrically connected, the connection member and the adherend of the semiconductor element are first heated under a predetermined temperature α less than the melting point of the connection member. Contact. As a result, the underfill material is softened, the connection member can easily enter the underfill material, and the contact between the connection member and the adherend can be set to a sufficient level. In this state, the connection member and the adherend are fixed to each other at a predetermined temperature β equal to or higher than the melting point of the connection member to obtain an electrical connection. Therefore, a semiconductor device with high connection reliability can be efficiently manufactured.

  In the said manufacturing method, it is preferable that the minimum melt viscosity in 100-200 degreeC of the said underfill material before thermosetting is 100 Pa.s or more and 20000 Pa.s or less. Thereby, the approach to the underfill material of a connection member can be made easy. In addition, generation of voids during electrical connection of the semiconductor elements and protrusion of the underfill material from the space between the semiconductor elements and the adherend can be prevented. In addition, the measurement of minimum melt viscosity is based on the procedure as described in an Example.

  In the manufacturing method, the viscosity of the underfill material before thermosetting at 23 ° C. is preferably 0.01 MPa · s or more and 100 MPa · s or less. When the underfill material before thermosetting has such a viscosity, the retention property of the semiconductor wafer during dicing and the handleability during work can be improved.

It is a cross-sectional schematic diagram which shows the sealing sheet which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram which shows the manufacturing process of the semiconductor device which concerns on one Embodiment of this invention.

  The present invention relates to a method of manufacturing a semiconductor device comprising an adherend, a semiconductor element electrically connected to the adherend, and an underfill material that fills a space between the adherend and the semiconductor element. A preparation step of preparing a sealing sheet comprising a dicing tape and an underfill material laminated on the dicing tape, a circuit surface on which a semiconductor wafer connecting member is formed, and an underfill of the sealing sheet A bonding step of bonding materials to each other under a reduced pressure of 1000 Pa or less, a dicing step of dicing the semiconductor wafer to form the semiconductor element with the underfill material, and a space between the adherend and the semiconductor element A connection step of electrically connecting the semiconductor element and the adherend through the connection member while filling the substrate with the underfill material. Hereinafter, an embodiment of the present invention will be described.

[Encapsulation sheet preparation process]
In the sealing sheet preparation step, a sealing sheet including a dicing tape and an underfill material laminated on the dicing tape is prepared.

(Sealing sheet)
As shown in FIG. 1, the sealing sheet 10 includes a dicing tape 1 and an underfill material 2 laminated on the dicing tape 1. The underfill material 2 does not have to be laminated on the entire surface of the dicing tape 1 as shown in FIG. 1 and is provided in a size sufficient for bonding to the semiconductor wafer 3 (see FIG. 2A). It only has to be done.

(Dicing tape)
The dicing tape 1 includes a substrate 1a and an adhesive layer 1b laminated on the substrate 1a. In addition, the underfill material 2 is laminated | stacked on the adhesive layer 1b.

(Base material)
The base material 1 a is a strength matrix of the sealing sheet 10. For example, polyolefins such as low density polyethylene, linear polyethylene, medium density polyethylene, high density polyethylene, ultra low density polyethylene, random copolymer polypropylene, block copolymer polypropylene, homopolyprolene, polybutene, polymethylpentene, ethylene-acetic acid Vinyl copolymer, ionomer resin, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) acrylic acid ester (random, alternating) copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, Polyester such as polyurethane, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyimide, polyetheretherketone, polyimide, polyetherimide, polyamide, wholly aromatic polyamide, polyphenylsulfur De, aramid (paper), glass, glass cloth, fluorine resin, polyvinyl chloride, polyvinylidene chloride, cellulose resin, silicone resin, metal (foil), paper, and the like. In the case where the pressure-sensitive adhesive layer 1b is of an ultraviolet curable type, the substrate 1a is preferably transparent to ultraviolet rays.

  Examples of the material for the substrate 1a include polymers such as a crosslinked body of the above resin. The plastic film may be used unstretched or may be uniaxially or biaxially stretched as necessary.

  The surface of the substrate 1a is chemically treated by conventional surface treatments such as chromic acid treatment, ozone exposure, flame exposure, high-voltage impact exposure, ionizing radiation treatment, etc. in order to improve adhesion and retention with adjacent layers. Alternatively, a physical treatment or a coating treatment with a primer (for example, an adhesive substance described later) can be performed.

  As the base material 1a, the same kind or different kinds can be appropriately selected and used, and if necessary, a blend of several kinds can be used. In addition, in order to impart antistatic ability to the base material 1a, a conductive material vapor deposition layer having a thickness of about 30 to 500 mm made of metal, alloy, oxides thereof, or the like is provided on the base material 1a. be able to. The substrate 1a may be a single layer or a multilayer of two or more.

  The thickness of the substrate 1a can be determined as appropriate, and is generally about 5 μm to 200 μm, preferably 35 μm to 120 μm.

  In addition, various additives (for example, a colorant, a filler, a plasticizer, an anti-aging agent, an antioxidant, a surfactant, a flame retardant, etc.) are added to the substrate 1a as long as the effects of the present invention are not impaired. May be included.

(Adhesive layer)
The pressure-sensitive adhesive used for forming the pressure-sensitive adhesive layer 1b can be controlled so that the semiconductor wafer or the semiconductor chip can be firmly held via the underfill material during dicing and the semiconductor chip with the underfill material can be peeled off during pick-up. There is no particular limitation. For example, a general pressure-sensitive adhesive such as an acrylic pressure-sensitive adhesive or a rubber-based pressure-sensitive adhesive can be used. As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive having an acrylic polymer as a base polymer from the viewpoint of cleanability of an electronic component that is difficult to contaminate semiconductor wafers, glass, etc., with an organic solvent such as ultrapure water or alcohol. Is preferred.

  Examples of the acrylic polymer include those using an acrylic ester as a main monomer component. Examples of the acrylic ester include (meth) acrylic acid alkyl ester (for example, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, pentyl ester, Isopentyl ester, hexyl ester, heptyl ester, octyl ester, 2-ethylhexyl ester, isooctyl ester, nonyl ester, decyl ester, isodecyl ester, undecyl ester, dodecyl ester, tridecyl ester, tetradecyl ester, hexadecyl ester , Octadecyl esters, eicosyl esters, etc., alkyl groups having 1 to 30 carbon atoms, especially 4 to 18 carbon linear or branched alkyl esters, etc.) and Meth) acrylic acid cycloalkyl esters (e.g., cyclopentyl ester, acrylic polymers such as one or more was used as a monomer component of the cyclohexyl ester etc.). In addition, (meth) acrylic acid ester means acrylic acid ester and / or methacrylic acid ester, and (meth) of the present invention has the same meaning.

  The acrylic polymer includes units corresponding to the other monomer components copolymerizable with the (meth) acrylic acid alkyl ester or cycloalkyl ester, if necessary, for the purpose of modifying cohesive force, heat resistance, and the like. You may go out. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; maleic anhydride Acid anhydride monomers such as itaconic anhydride; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate Hydroxyl group-containing monomers such as 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; The Sulfonic acid groups such as lensulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid Containing monomers; Phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate; acrylamide, acrylonitrile and the like. One or more of these copolymerizable monomer components can be used. The amount of these copolymerizable monomers used is preferably 40% by weight or less based on the total monomer components.

  Furthermore, since the acrylic polymer is crosslinked, a polyfunctional monomer or the like can be included as a monomer component for copolymerization as necessary. Examples of such polyfunctional monomers include hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy (meth) acrylate, polyester (meth) acrylate, urethane (meth) Examples include acrylates. These polyfunctional monomers can also be used alone or in combination of two or more. The amount of the polyfunctional monomer used is preferably 30% by weight or less of the total monomer components from the viewpoint of adhesive properties and the like.

  The acrylic polymer can be obtained by subjecting a single monomer or a mixture of two or more monomers to polymerization. The polymerization can be performed by any method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization and the like. From the viewpoint of preventing contamination of a clean adherend, the content of the low molecular weight substance is preferably small. From this point, the number average molecular weight of the acrylic polymer is preferably 300,000 or more, more preferably about 400,000 to 3,000,000.

  Moreover, in order to increase the number average molecular weight of the acrylic polymer or the like as the base polymer, an external cross-linking agent can be appropriately employed for the pressure-sensitive adhesive. Specific examples of the external crosslinking method include a method in which a so-called crosslinking agent such as a polyisocyanate compound, an epoxy compound, an aziridine compound, or a melamine crosslinking agent is added and reacted. When using an external cross-linking agent, the amount used is appropriately determined depending on the balance with the base polymer to be cross-linked, and further depending on the intended use as an adhesive. Generally, it is preferable to add about 5 parts by weight or less, and further 0.1 to 5 parts by weight with respect to 100 parts by weight of the base polymer. Furthermore, additives such as various conventionally known tackifiers and anti-aging agents may be used for the pressure-sensitive adhesive, if necessary, in addition to the above components.

  The pressure-sensitive adhesive layer 1b can be formed of a radiation curable pressure-sensitive adhesive. The radiation curable pressure-sensitive adhesive can increase the degree of crosslinking by irradiation with radiation such as ultraviolet rays, and can easily reduce its adhesive strength, and can be easily picked up. Examples of radiation include X-rays, ultraviolet rays, electron beams, α rays, β rays, and neutron rays.

  As the radiation-curable pressure-sensitive adhesive, those having a radiation-curable functional group such as a carbon-carbon double bond and exhibiting adhesiveness can be used without particular limitation. Examples of the radiation curable pressure-sensitive adhesive include additive-type radiation curable pressure-sensitive adhesives in which radiation-curable monomer components and oligomer components are blended with general pressure-sensitive pressure-sensitive adhesives such as the above-mentioned acrylic pressure-sensitive adhesives and rubber-based pressure-sensitive adhesives. An agent can be illustrated.

  Examples of the radiation curable monomer component to be blended include urethane oligomer, urethane (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol. Examples include stall tetra (meth) acrylate, dipentaerystol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, 1,4-butanediol di (meth) acrylate, and the like. Examples of the radiation curable oligomer component include various oligomers such as urethane, polyether, polyester, polycarbonate, and polybutadiene, and those having a weight average molecular weight in the range of about 100 to 30000 are suitable. The compounding amount of the radiation curable monomer component or oligomer component can be appropriately determined in such an amount that the adhesive force of the pressure-sensitive adhesive layer can be reduced depending on the type of the pressure-sensitive adhesive layer. Generally, the amount is, for example, about 5 to 500 parts by weight, preferably about 40 to 150 parts by weight with respect to 100 parts by weight of the base polymer such as an acrylic polymer constituting the pressure-sensitive adhesive.

  In addition to the additive-type radiation-curable adhesive described above, the radiation-curable adhesive has a carbon-carbon double bond in the polymer side chain, main chain, or main chain terminal as a base polymer. Intrinsic radiation curable adhesives using Intrinsic radiation curable adhesives do not need to contain oligomer components, which are low molecular components, or do not contain many, so they are stable without the oligomer components, etc. moving through the adhesive over time. This is preferable because an adhesive layer having a layered structure can be formed.

  As the base polymer having a carbon-carbon double bond, those having a carbon-carbon double bond and having adhesiveness can be used without particular limitation. As such a base polymer, an acrylic polymer having a basic skeleton is preferable. Examples of the basic skeleton of the acrylic polymer include the acrylic polymers exemplified above.

  The method for introducing a carbon-carbon double bond into the acrylic polymer is not particularly limited, and various methods can be adopted. However, it is easy to design a molecule by introducing a carbon-carbon double bond into a polymer side chain. . For example, after a monomer having a functional group is copolymerized in advance with an acrylic polymer, a compound having a functional group capable of reacting with the functional group and a carbon-carbon double bond is converted into a radiation-curable carbon-carbon double bond. Examples of the method include condensation or addition reaction while maintaining the above.

  Examples of combinations of these functional groups include carboxylic acid groups and epoxy groups, carboxylic acid groups and aziridyl groups, hydroxyl groups and isocyanate groups. Among these combinations of functional groups, a combination of a hydroxyl group and an isocyanate group is preferable because of easy tracking of the reaction. In addition, the functional group may be on either side of the acrylic polymer and the compound as long as the acrylic polymer having the carbon-carbon double bond is generated by a combination of these functional groups. In the above preferred combination, it is preferable that the acrylic polymer has a hydroxyl group and the compound has an isocyanate group. In this case, examples of the isocyanate compound having a carbon-carbon double bond include methacryloyl isocyanate, 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α, α-dimethylbenzyl isocyanate, and the like. As the acrylic polymer, those obtained by copolymerizing the above-exemplified hydroxy group-containing monomers, ether compounds of 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, or the like are used.

  As the internal radiation curable pressure-sensitive adhesive, the base polymer (particularly acrylic polymer) having the carbon-carbon double bond can be used alone, but the radiation curable monomer is not deteriorated. Components and oligomer components can also be blended. The radiation-curable oligomer component or the like is usually in the range of 30 parts by weight, preferably in the range of 0 to 10 parts by weight with respect to 100 parts by weight of the base polymer.

  The radiation curable pressure-sensitive adhesive preferably contains a photopolymerization initiator when cured by ultraviolet rays or the like. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone, α-hydroxy-α, α′-dimethylacetophenone, 2-methyl-2-hydroxypropio Α-ketol compounds such as phenone and 1-hydroxycyclohexyl phenyl ketone; methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- ( Acetophenone compounds such as methylthio) -phenyl] -2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether and anisoin methyl ether; ketal compounds such as benzyldimethyl ketal; 2-naphthalenesulfo D Aromatic sulfonyl chloride compounds such as luchloride; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; benzophenone, benzoylbenzoic acid, 3,3′-dimethyl Benzophenone compounds such as -4-methoxybenzophenone; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2 Thioxanthone compounds such as 1,4-diethylthioxanthone and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketone; acyl phosphinoxide; acyl phosphonate. The compounding quantity of a photoinitiator is about 0.05-20 weight part with respect to 100 weight part of base polymers, such as an acryl-type polymer which comprises an adhesive.

  In addition, when curing inhibition by oxygen occurs during irradiation, it is desirable to block oxygen (air) from the surface of the radiation curable pressure-sensitive adhesive layer 1b by some method. For example, a method of covering the surface of the pressure-sensitive adhesive layer 1b with a separator, a method of irradiating radiation such as ultraviolet rays in a nitrogen gas atmosphere, and the like can be mentioned.

  In the pressure-sensitive adhesive layer 1b, various additives (for example, a colorant, a thickener, a bulking agent, a filler, a tackifier, a plasticizer, an antiaging agent, Antioxidants, surfactants, crosslinking agents, etc.) may be included.

  The thickness of the pressure-sensitive adhesive layer 1 b is not particularly limited, but is preferably about 1 to 80 μm from the viewpoint of preventing chipping of the chip cut surface and compatibility of fixing and holding the underfill material 2. Preferably it is 2-50 micrometers, More preferably, it is 5-35 micrometers.

(Underfill material)
The underfill material 2 in the present embodiment can be used as a sealing film that fills a space between a surface-mounted semiconductor element and an adherend. As a constituent material of the underfill material, a combination of a thermoplastic resin and a thermosetting resin can be used. A thermoplastic resin or a thermosetting resin alone can also be used.

  Examples of the thermoplastic resin include natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, heat Examples thereof include plastic polyimide resins, polyamide resins such as 6-nylon and 6,6-nylon, phenoxy resins, acrylic resins, saturated polyester resins such as PET and PBT, polyamideimide resins, and fluorine resins. These thermoplastic resins can be used alone or in combination of two or more. Of these thermoplastic resins, an acrylic resin that has few ionic impurities and high heat resistance and can ensure the reliability of the semiconductor element is particularly preferable.

  The acrylic resin is not particularly limited, and includes one or two or more esters of acrylic acid or methacrylic acid having a linear or branched alkyl group having 30 or less carbon atoms, particularly 4 to 18 carbon atoms. Examples include polymers as components. Examples of the alkyl group include a methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, t-butyl group, isobutyl group, amyl group, isoamyl group, hexyl group, heptyl group, cyclohexyl group, 2 -Ethylhexyl group, octyl group, isooctyl group, nonyl group, isononyl group, decyl group, isodecyl group, undecyl group, lauryl group, tridecyl group, tetradecyl group, stearyl group, octadecyl group, dodecyl group and the like.

  In addition, the other monomer forming the polymer is not particularly limited, and examples thereof include acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Carboxyl group-containing monomers such as acid anhydride monomers such as maleic anhydride or itaconic anhydride, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4- (meth) acrylic acid 4- Hydroxybutyl, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate or (4-hydroxymethylcyclohexyl) -Methyla Hydroxyl group-containing monomers such as relate, styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate or (meth) Examples thereof include sulfonic acid group-containing monomers such as acryloyloxynaphthalene sulfonic acid, and phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate.

  Examples of the thermosetting resin include phenol resin, amino resin, unsaturated polyester resin, epoxy resin, polyurethane resin, silicone resin, and thermosetting polyimide resin. These resins can be used alone or in combination of two or more. In particular, an epoxy resin containing a small amount of ionic impurities or the like that corrode semiconductor elements is preferable. Moreover, as a hardening | curing agent of an epoxy resin, a phenol resin is preferable.

  The epoxy resin is not particularly limited as long as it is generally used as an adhesive composition, for example, bisphenol A type, bisphenol F type, bisphenol S type, brominated bisphenol A type, hydrogenated bisphenol A type, bisphenol AF type. Biphenyl type, naphthalene type, fluorene type, phenol novolak type, orthocresol novolak type, trishydroxyphenylmethane type, tetraphenylolethane type, etc., bifunctional epoxy resin or polyfunctional epoxy resin, or hydantoin type, trisglycidyl isocyanurate Type or glycidylamine type epoxy resin is used. These can be used alone or in combination of two or more. Of these epoxy resins, novolac type epoxy resins, biphenyl type epoxy resins, trishydroxyphenylmethane type resins or tetraphenylolethane type epoxy resins are particularly preferred. This is because these epoxy resins are rich in reactivity with a phenol resin as a curing agent and are excellent in heat resistance and the like.

  Further, the phenol resin acts as a curing agent for the epoxy resin, for example, a novolac type phenol resin such as a phenol novolac resin, a phenol aralkyl resin, a cresol novolac resin, a tert-butylphenol novolac resin, a nonylphenol novolac resin, Examples include resol-type phenolic resins and polyoxystyrenes such as polyparaoxystyrene. These can be used alone or in combination of two or more. Of these phenol resins, phenol novolac resins and phenol aralkyl resins are particularly preferred. This is because the connection reliability of the semiconductor device can be improved.

  The mixing ratio of the epoxy resin and the phenol resin is preferably such that, for example, the hydroxyl group in the phenol resin is 0.5 to 2.0 equivalents per equivalent of epoxy group in the epoxy resin component. More preferred is 0.8 to 1.2 equivalents. That is, if the blending ratio of both is out of the above range, sufficient curing reaction does not proceed and the properties of the cured epoxy resin are likely to deteriorate.

  In the present invention, an underfill material using an epoxy resin, a phenol resin and an acrylic resin is particularly preferable. Since these resins have few ionic impurities and high heat resistance, the reliability of the semiconductor element can be ensured. In this case, the mixing ratio of the epoxy resin and the phenol resin is 10 to 200 parts by weight with respect to 100 parts by weight of the acrylic resin component.

  The thermosetting acceleration catalyst for epoxy resin and phenol resin is not particularly limited, and can be appropriately selected from known thermosetting acceleration catalysts. A thermosetting acceleration | stimulation catalyst can be used individually or in combination of 2 or more types. As the thermosetting acceleration catalyst, for example, an amine curing accelerator, a phosphorus curing accelerator, an imidazole curing accelerator, a boron curing accelerator, a phosphorus-boron curing accelerator, or the like can be used.

  A flux may be added to the underfill material 2 in order to remove the oxide film on the surface of the solder bump and facilitate mounting of the semiconductor element. The flux is not particularly limited, and a conventionally known compound having a flux action can be used.For example, diphenolic acid, adipic acid, acetylsalicylic acid, benzoic acid, benzylic acid, azelaic acid, benzylbenzoic acid, malonic acid, 2,2-bis (hydroxymethyl) propionic acid, salicylic acid, o-methoxybenzoic acid, m-hydroxybenzoic acid, succinic acid, 2,6-dimethoxymethylparacresol, benzoic hydrazide, carbohydrazide, malonic dihydrazide, succinic acid Acid dihydrazide, glutaric acid dihydrazide, salicylic acid hydrazide, iminodiacetic acid dihydrazide, itaconic acid dihydrazide, citric acid trihydrazide, thiocarbohydrazide, benzophenone hydrazone, 4,4'-oxybisbenzenesulfonylhydrazide and Adipic acid dihydrazide, and the like. The addition amount of the flux is only required to exhibit the above flux effect, and is usually about 0.1 to 20 parts by weight with respect to 100 parts by weight of the resin component contained in the underfill material.

  In the present embodiment, the underfill material 2 may be colored as necessary. In the underfill material 2, the color exhibited by coloring is not particularly limited. For example, black, blue, red, green, and the like are preferable. In coloring, it can be appropriately selected from known colorants such as pigments and dyes.

  When the underfill material 2 of the present embodiment is previously crosslinked to some extent, a polyfunctional compound that reacts with a functional group at the molecular chain end of the polymer is added as a crosslinking agent during the production. Good. Thereby, the adhesive property under high temperature can be improved and heat resistance can be improved.

  As the crosslinking agent, polyisocyanate compounds such as tolylene diisocyanate, diphenylmethane diisocyanate, p-phenylene diisocyanate, 1,5-naphthalene diisocyanate, an adduct of polyhydric alcohol and diisocyanate are more preferable. The addition amount of the crosslinking agent is usually preferably 0.05 to 7 parts by weight with respect to 100 parts by weight of the polymer. When the amount of the cross-linking agent is more than 7 parts by weight, the adhesive force is lowered, which is not preferable. On the other hand, if it is less than 0.05 parts by weight, the cohesive force is insufficient, which is not preferable. Moreover, you may make it include other polyfunctional compounds, such as an epoxy resin, together with such a polyisocyanate compound as needed.

  The underfill material 2 can be appropriately mixed with an inorganic filler. The blending of the inorganic filler makes it possible to impart conductivity, improve thermal conductivity, adjust the storage elastic modulus, and the like.

  Examples of the inorganic filler include silica, clay, gypsum, calcium carbonate, barium sulfate, alumina, beryllium oxide, silicon carbide, silicon nitride, and other ceramics, aluminum, copper, silver, gold, nickel, chromium, lead. And various inorganic powders made of metals such as tin, zinc, palladium, solder, or alloys, and other carbons. These can be used alone or in combination of two or more. Among these, silica, particularly fused silica is preferably used.

  Although the average particle diameter of the inorganic filler is not particularly limited, it is preferably in the range of 0.005 to 10 μm, more preferably in the range of 0.01 to 5 μm, and still more preferably 0.1 to 2. 0.0 μm. When the average particle size of the inorganic filler is less than 0.005 μm, the flexibility of the underfill material is reduced. On the other hand, when the average particle size exceeds 10 μm, the particle size is large with respect to the gap sealed by the underfill material, which causes a decrease in sealing performance. In the present invention, inorganic fillers having different average particle sizes may be used in combination. The average particle size is a value determined by a photometric particle size distribution meter (manufactured by HORIBA, apparatus name: LA-910).

  The blending amount of the inorganic filler is preferably 10 to 400 parts by weight, more preferably 50 to 250 parts by weight with respect to 100 parts by weight of the organic resin component. If the blending amount of the inorganic filler is less than 10 parts by weight, the storage elastic modulus may be lowered and the stress reliability of the package may be greatly impaired. On the other hand, if it exceeds 400 parts by weight, the fluidity of the underfill material 2 may be reduced, and may not be sufficiently embedded in the irregularities of the substrate or semiconductor element, causing voids or cracks.

  In addition to the said inorganic filler, other additives can be suitably mix | blended with the underfill material 2 as needed. Examples of other additives include flame retardants, silane coupling agents, ion trapping agents, and the like. Examples of the flame retardant include antimony trioxide, antimony pentoxide, brominated epoxy resin, and the like. These can be used alone or in combination of two or more. Examples of the silane coupling agent include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and the like. These compounds can be used alone or in combination of two or more. Examples of the ion trapping agent include hydrotalcites and bismuth hydroxide. These can be used alone or in combination of two or more.

  In this embodiment, the minimum melt viscosity at 100 to 200 ° C. of the underfill material 2 before thermosetting is preferably 100 Pa · s or more and 20000 Pa · s or less, and is 1000 Pa · s or more and 10,000 Pa · s or less. Is more preferable. By setting the minimum melt viscosity within the above range, the connection member 4 (see FIG. 2A) can easily enter the underfill material 2. In addition, generation of voids during electrical connection of the semiconductor element 5 and protrusion of the underfill material 2 from the space between the semiconductor element 5 and the adherend 6 can be prevented (FIG. 2E). reference).

  Further, the viscosity at 23 ° C. of the underfill material 2 before thermosetting is preferably 0.01 MPa · s or more and 100 MPa · s or less, and more preferably 0.1 MPa · s or more and 10 MPa · s or less. . Since the underfill material before thermosetting has a viscosity in the above range, the holding property of the semiconductor wafer 3 (see FIG. 2B) during dicing and the handleability during work can be improved. In addition, the measurement of a viscosity can be performed according to the measuring method of minimum melt viscosity.

  Further, the water absorption rate of the underfill material 2 before thermosetting under the conditions of a temperature of 23 ° C. and a humidity of 70% is preferably 1% by weight or less, and more preferably 0.5% by weight or less. When the underfill material 2 has a water absorption rate as described above, absorption of moisture into the underfill material 2 is suppressed, and generation of voids when the semiconductor element 5 is mounted can be more efficiently suppressed. The lower limit of the water absorption rate is preferably as small as possible, substantially 0% by weight is preferable, and 0% by weight is more preferable.

  Although the thickness of the underfill material 2 (total thickness in the case of multiple layers) is not particularly limited, considering the strength of the underfill material 2 and the filling property of the space between the semiconductor element 5 and the adherend 6, it is 10 μm or more. It may be about 100 μm or less. Note that the thickness of the underfill material 2 may be appropriately set in consideration of the gap between the semiconductor element 5 and the adherend 6 and the height of the connection member.

  The underfill material 2 of the sealing sheet 10 is preferably protected by a separator (not shown). The separator has a function as a protective material that protects the underfill material 2 until it is practically used. The separator is peeled off when the semiconductor wafer 3 is stuck on the underfill material 2 of the sealing sheet. As the separator, a plastic film or paper surface-coated with a release agent such as polyethylene terephthalate (PET), polyethylene, polypropylene, a fluorine release agent, or a long-chain alkyl acrylate release agent can be used.

(Method for producing sealing sheet)
The encapsulating sheet 10 according to the present embodiment can be produced, for example, by preparing the dicing tape 1 and the underfill material 2 separately and finally bonding them together. Specifically, it can be produced according to the following procedure.

  First, the base material 1a can be formed by a conventionally known film forming method. Examples of the film forming method include a calendar film forming method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, a co-extrusion method, and a dry lamination method.

  Next, a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer is prepared. Resin, additive, etc. which were demonstrated by the term of the adhesive layer are mix | blended with the adhesive composition. After the prepared pressure-sensitive adhesive composition is applied on the substrate 1a to form a coating film, the coating film is dried under predetermined conditions (heat-crosslinked as necessary) to form the pressure-sensitive adhesive layer 1b. . It does not specifically limit as a coating method, For example, roll coating, screen coating, gravure coating, etc. are mentioned. As drying conditions, for example, the drying temperature is 80 to 150 ° C. and the drying time is 0.5 to 5 minutes. Moreover, after apply | coating an adhesive composition on a separator and forming a coating film, the coating film may be dried on the said dry conditions, and the adhesive layer 1b may be formed. Then, the adhesive layer 1b is bonded together with a separator on the base material 1a. Thereby, the dicing tape 1 provided with the base material 1a and the adhesive layer 1b is produced.

  The underfill material 2 is produced as follows, for example. First, an adhesive composition that is a material for forming the underfill material 2 is prepared. As described in the section of the underfill material, the adhesive composition contains a thermoplastic component, an epoxy resin, various additives, and the like.

  Next, after applying the prepared adhesive composition on the base separator so as to have a predetermined thickness to form a coating film, the coating film is dried under predetermined conditions to form an underfill material. It does not specifically limit as a coating method, For example, roll coating, screen coating, gravure coating, etc. are mentioned. As drying conditions, for example, the drying temperature is 70 to 160 ° C. and the drying time is 1 to 5 minutes. Moreover, after apply | coating an adhesive composition on a separator and forming a coating film, an underfill material may be formed by drying a coating film on the said drying conditions. Then, an underfill material is bonded together with a separator on a base material separator.

  Subsequently, the separator is peeled off from each of the dicing tape 1 and the underfill material 2, and both are bonded so that the underfill material and the pressure-sensitive adhesive layer become a bonding surface. Bonding can be performed by, for example, pressure bonding. At this time, the lamination temperature is not particularly limited, and for example, 30 to 100 ° C is preferable, and 40 to 80 ° C is more preferable. Further, the linear pressure is not particularly limited, and for example, 0.98 to 196 N / cm is preferable, and 9.8 to 98 N / cm is more preferable. Next, the base material separator on the underfill material is peeled off, and the sealing sheet according to the present embodiment is obtained.

[Lamination process]
In the bonding step, the circuit surface 3a on which the connecting member 4 of the semiconductor wafer 3 is formed and the underfill material 2 of the sealing sheet 10 are bonded under reduced pressure of 1000 Pa or less (see FIG. 2A).

(Semiconductor wafer)
A plurality of connection members 4 are formed on the circuit surface 3a of the semiconductor wafer 3 (see FIG. 2A). The material of the connection member such as a bump or a conductive material is not particularly limited. For example, a tin-lead metal material, a tin-silver metal material, a tin-silver-copper metal material, a tin-zinc metal material, Examples thereof include solders (alloys) such as a tin-zinc-bismuth metal material, a gold metal material, and a copper metal material. The height of the connecting member is also determined according to the application, and is generally about 15 to 100 μm. Of course, the height of each connection member in the semiconductor wafer 3 may be the same or different.

In the method for manufacturing a semiconductor device according to the present embodiment, the thickness of the underfill material includes a height X (μm) of the connecting member formed on the surface of the semiconductor wafer and a thickness Y (μm) of the underfill material. However, it is preferable to satisfy | fill the following relationship.
0.5 ≦ Y / X ≦ 2

  When the height X (μm) of the connecting member and the thickness Y (μm) of the cured film satisfy the above relationship, the space between the semiconductor element and the adherend can be sufficiently filled. Further, excessive protrusion of the underfill material from the space can be prevented, and contamination of the semiconductor element by the underfill material can be prevented. In addition, when the height of each connection member differs, the height of the highest connection member is used as a reference.

(Lamination)
As shown in FIG. 2 (a), first, a separator arbitrarily provided on the underfill material 2 of the sealing sheet 10 is appropriately peeled off, and the circuit surface 3a on which the connecting member 4 of the semiconductor wafer 3 is formed. And the underfill material 2 are opposed to each other, and the underfill material 2 and the semiconductor wafer 3 are bonded together (mounting process).

  The method of bonding is not particularly limited, but a method by pressure bonding is preferable. The crimping is usually performed by a known pressing means such as a crimping roll while applying a pressure of 0.1 to 1 MPa, more preferably 0.3 to 0.7 MPa. Under the present circumstances, you may make it press-fit, heating at about 40-100 degreeC.

    The method of bonding is not particularly limited, but a method by pressure bonding is preferable. The crimping is usually performed by a known pressing means such as a crimping roll while applying a pressure of 0.1 to 1 MPa, more preferably 0.2 to 0.7 MPa. Under the present circumstances, you may make it press-fit, heating at about 40-100 degreeC.

  In this embodiment, the semiconductor wafer and the underfill material are bonded together under a reduced pressure of 1000 Pa or less. The upper limit of the decompression condition is preferably 500 Pa or less, more preferably 300 Pa or less. In addition, although the minimum of pressure reduction conditions is not specifically limited, What is necessary is just 10 Pa or more from the point of productivity. By bonding together under the specified decompression conditions, it is possible to significantly reduce bubbles at the interface between the semiconductor wafer and the underfill material, thereby improving adhesion, thereby suppressing the generation of voids at the interface. can do. As a result, a semiconductor device having excellent connection reliability between the semiconductor wafer and the adherend can be efficiently manufactured.

[Grinding process]
In the grinding step, the surface (that is, the back surface) 3b opposite to the circuit surface 3a of the semiconductor wafer 3 is ground (see FIG. 2B). The thin processing machine used for back surface grinding of the semiconductor wafer 3 is not particularly limited, and examples thereof include a grinding machine (back grinder) and a polishing pad. Further, the back surface grinding may be performed by a chemical method such as etching. The back surface grinding is performed until the semiconductor wafer has a desired thickness (for example, 700 to 25 μm).

[Dicing process]
In the dicing step, as shown in FIG. 2C, the semiconductor wafer 3 is diced to form the semiconductor element 5 with an underfill material. By passing through a dicing process, the semiconductor wafer 3 is cut into a predetermined size and divided into pieces (small pieces), and a semiconductor chip (semiconductor element) 5 is manufactured. The semiconductor chip 5 obtained here is integrated with the underfill material 2 cut into the same shape. Dicing is performed according to a conventional method from the surface 3b opposite to the circuit surface 3a on which the underfill material 2 of the semiconductor wafer 3 is bonded. The alignment of the cut portion can be performed by image recognition using direct light or indirect light.

  In addition, when expanding a sealing sheet following a dicing process, this expansion can be performed using a conventionally well-known expanding apparatus. The expanding device includes a donut-shaped outer ring that can push down the sealing sheet through a dicing ring, and an inner ring that has a smaller diameter than the outer ring and supports the sealing sheet. By this expanding process, it is possible to prevent adjacent semiconductor chips from coming into contact with each other and being damaged in a pickup process described later.

[Pickup process]
In order to collect the semiconductor chip 5 adhered and fixed to the sealing sheet, as shown in FIG. 2C, the semiconductor chip 5 with the underfill material 2 is picked up, and the semiconductor chip 5 and the underfill material 3 are picked up. The laminate A is peeled from the dicing tape 1.

  The pickup method is not particularly limited, and various conventionally known methods can be employed. For example, a method of pushing up individual semiconductor chips from the base material side of the sealing sheet with a needle and picking up the pushed-up semiconductor chips with a pickup device can be mentioned. The picked-up semiconductor chip 5 constitutes a laminate A integrally with the underfill material 2 bonded to the circuit surface 3a.

  Here, when the pressure-sensitive adhesive layer 1b is an ultraviolet curable type, the pickup is performed after the pressure-sensitive adhesive layer 1b is irradiated with ultraviolet rays. Thereby, the adhesive force with respect to the underfill material 2 of the adhesive layer 1b falls, and peeling of the semiconductor chip 5 becomes easy. As a result, the pickup can be performed without damaging the semiconductor chip 5. Conditions such as irradiation intensity and irradiation time at the time of ultraviolet irradiation are not particularly limited, and may be set as necessary. Moreover, as a light source used for ultraviolet irradiation, for example, a low-pressure mercury lamp, a low-pressure high-power lamp, a medium-pressure mercury lamp, an electrodeless mercury lamp, a xenon flash lamp, an excimer lamp, an ultraviolet LED, or the like can be used.

[Mounting process]
In the mounting process, the semiconductor element 5 and the adherend 6 are electrically connected via the connecting member 4 while filling the space between the adherend 6 and the semiconductor element 5 with the underfill material 2 (FIG. 2 ( d)). Specifically, the semiconductor chip 5 of the stacked body A is fixed to the adherend 6 according to a conventional method with the circuit surface 3a of the semiconductor chip 5 facing the adherend 6. For example, bumps (connection members) 4 formed on the semiconductor chip 5 are brought into contact with a bonding conductive material 7 (solder or the like) attached to the connection pads of the adherend 6 while pressing the conductive material. By melting, the electrical connection between the semiconductor chip 5 and the adherend 6 can be secured, and the semiconductor chip 5 can be fixed to the adherend 6. Since the underfill material 2 is affixed to the circuit surface 3 a of the semiconductor chip 5, the space between the semiconductor chip 5 and the adherend 6 as well as the electrical connection between the semiconductor chip 5 and the adherend 6. Is filled with the underfill material 2.

  Generally, the heating condition in the mounting process is 100 to 300 ° C., and the pressurizing condition is 0.5 to 500 N. Moreover, you may perform the thermocompression-bonding process in a mounting process in multistep. For example, it is possible to adopt a procedure in which treatment is performed at 150 ° C. and 100 N for 10 seconds and then treatment is performed at 300 ° C. and 100 to 200 N for 10 seconds. By performing thermocompression bonding in multiple stages, the resin between the connection member and the pad can be efficiently removed, and a better metal-to-metal bond can be obtained.

  As the adherend 6, various substrates such as a lead frame and a circuit board (such as a wiring circuit board), and other semiconductor elements can be used. The material of the substrate is not particularly limited, and examples thereof include a ceramic substrate and a plastic substrate. Examples of the plastic substrate include an epoxy substrate, a bismaleimide triazine substrate, a polyimide substrate, and a glass epoxy substrate.

  In the mounting process, one or both of the connection member and the conductive material are melted to connect the bumps 4 on the connection member forming surface 3a of the semiconductor chip 5 and the conductive material 7 on the surface of the adherend 6. However, the temperature at the time of melting of the bumps 4 and the conductive material 7 is usually about 260 ° C. (for example, 250 ° C. to 300 ° C.). The sealing sheet according to the present embodiment can have heat resistance that can withstand high temperatures in the mounting process by forming the underfill material 2 with an epoxy resin or the like.

[Underfill material curing process]
After the electrical connection between the semiconductor element 5 and the adherend 6 is performed, the underfill material 2 is cured by heating. Thereby, the surface of the semiconductor element 5 can be protected, and the connection reliability between the semiconductor element 5 and the adherend 6 can be ensured. It does not specifically limit as heating temperature for hardening of an underfill material, What is necessary is just about 150-250 degreeC. Note that this step can be omitted when the underfill material is also cured by heating in the mounting step.

[Sealing process]
Next, a sealing step may be performed in order to protect the entire semiconductor device 20 including the mounted semiconductor chip 5. The sealing step is performed using a sealing resin. Although it does not specifically limit as sealing conditions at this time, Usually, the thermosetting of the sealing resin is performed by heating at 175 ° C. for 60 seconds to 90 seconds, but the present invention is not limited thereto, For example, it can be cured at 165 ° C. to 185 ° C. for several minutes.

  The sealing resin is not particularly limited as long as it is an insulating resin (insulating resin), and can be appropriately selected from sealing materials such as known sealing resins. Is more preferable. As sealing resin, the resin composition containing an epoxy resin etc. are mentioned, for example. Examples of the epoxy resin include the epoxy resins exemplified above. Moreover, as a sealing resin by the resin composition containing an epoxy resin, in addition to an epoxy resin, a thermosetting resin other than an epoxy resin (such as a phenol resin) or a thermoplastic resin may be included as a resin component. Good. In addition, as a phenol resin, it can utilize also as a hardening | curing agent of an epoxy resin, As such a phenol resin, the phenol resin illustrated above etc. are mentioned.

[Semiconductor device]
Next, a semiconductor device obtained using the sealing sheet will be described with reference to the drawing (see FIG. 2D). In the semiconductor device 20 according to the present embodiment, the semiconductor element 5 and the adherend 6 are connected via the bump (connection member) 4 formed on the semiconductor element 5 and the conductive material 7 provided on the adherend 6. Are electrically connected. An underfill material 2 is disposed between the semiconductor element 5 and the adherend 6 so as to fill the space. Since the semiconductor device 20 is obtained by the above manufacturing method using the sealing sheet 10, generation of voids is suppressed between the semiconductor element 5 and the underfill material 2. Therefore, the surface protection of the semiconductor element 5 and the filling of the space between the semiconductor element 5 and the adherend 6 are at a sufficient level, and the semiconductor device 20 can exhibit high reliability.

  Hereinafter, preferred embodiments of the present invention will be described in detail by way of example. However, the materials, blending amounts, and the like described in the examples are not intended to limit the scope of the present invention only to those unless otherwise specified. The term “parts” means parts by weight.

[Example 1]
(Preparation of sealing sheet)
Acrylic ester polymer based on ethyl acrylate-methyl methacrylate (trade name “Paracron W-197CM” manufactured by Negami Kogyo Co., Ltd.): 100 parts, epoxy resin 1 (trade name “Epicoat 1004” JER stock 56 parts, epoxy resin 2 (trade name “Epicoat 828” manufactured by JER Corporation): 19 parts, phenol resin (trade name “Millex XLC-4L” manufactured by Mitsui Chemicals): 75 parts, spherical silica ( Product name “SO-25R” manufactured by Admatechs Co., Ltd.): 167 parts, organic acid (trade name “Orthoanisic acid” manufactured by Tokyo Chemical Industry Co., Ltd.): 1.3 parts, imidazole catalyst (trade name “2PHZ-PW” Shikoku Chemicals) (Manufactured by Co., Ltd.): A solution of an adhesive composition in which 1.3 parts are dissolved in methyl ethyl ketone and the solid content concentration becomes 23.6% by weight. It was prepared.

  By applying this adhesive composition solution on a release film made of a polyethylene terephthalate film having a thickness of 50 μm subjected to silicone release treatment as a release liner (separator), and then drying at 130 ° C. for 2 minutes, An underfill material having a thickness of 45 μm was produced.

  The said underfill material was bonded together on the adhesive layer of the dicing tape (Brand name "V-8-T", Nitto Denko Corporation make) using the hand roller, and the sealing sheet was produced.

(Fabrication of semiconductor devices)
Prepare a silicon wafer with single-sided bumps with bumps formed on one side, and bond the prepared sealing sheet to the surface on which the bumps of the silicon wafer with single-sided bumps are formed, with an underfill material as the bonding surface Pasted together. As a silicon wafer with a single-sided bump, the following was used. The bonding conditions are as follows. The ratio (Y / X) of the thickness Y (= 45 μm) of the underfill material to the height X (= 45 μm) of the connecting member was 1.

<Silicon wafer with single-sided bump>
Silicon wafer diameter: 8 inches Silicon wafer thickness: 0.2 mm (200 μm)
Bump height: 45μm
Bump pitch: 50 μm
Bump material: Solder + Copper pillar

<Bonding conditions>
Pasting device: Product name “DSA840-WS” manufactured by Nitto Seiki Co., Ltd. Pasting speed: 5 mm / min
Pasting pressure: 0.25 MPa
Stage temperature at the time of pasting: 80 ° C
Decompression degree when pasting: 150 Pa

  Next, after bonding the single-sided bumped silicon wafer and the sealing sheet according to the above procedure, the semiconductor wafer was diced under the following conditions. Dicing was fully cut so as to obtain a chip size of 7.3 mm square.

<Dicing conditions>
Dicing machine: Trade name “DFD-6361” manufactured by Disco Corporation Dicing ring: “2-8-1” (manufactured by Disco Corporation)
Dicing speed: 30mm / sec
Dicing blade:
Z1; "203O-SE 27HCDD" manufactured by DISCO
Z2: “203O-SE 27HCBB” manufactured by Disco Corporation
Dicing blade rotation speed:
Z1; 40,000 rpm
Z2; 45,000 rpm
Cut method: Step cut Wafer chip size: 7.3mm square

  Next, the laminated body of the underfill material and the semiconductor chip with single-sided bumps was picked up by a push-up method using a needle from the base material side of each sealing sheet. The pickup conditions are as follows.

<Pickup conditions>
Pickup device: Brand name “SPA-300” manufactured by Shinkawa Co., Ltd. Number of needles: 9 Needle push-up amount: 500 μm (0.5 mm)
Needle push-up speed: 20 mm / second Pickup time: 1 second Expanding amount: 3 mm

  Finally, under the following thermocompression bonding conditions, the semiconductor chip was mounted on the BGA substrate by thermocompression bonding with the bump forming surface of the semiconductor chip facing the BGA substrate. Thus, a semiconductor device in which the semiconductor chip was mounted on the BGA substrate was obtained. In this step, a two-step process of performing thermocompression bonding under thermocompression bonding condition 2 following thermocompression bonding condition 1 was performed.

<Thermocompression condition 1>
Pickup device: Product name “FCB-3” manufactured by Panasonic Heating temperature: 150 ° C.
Load: 98N
Holding time: 10 seconds

<Thermocompression condition 2>
Pickup device: Product name “FCB-3” manufactured by Panasonic Heating temperature: 260 ° C.
Load: 98N
Holding time: 10 seconds

[Example 2]
A semiconductor device was fabricated in the same manner as in Example 1 except that the semiconductor wafer and the underfill material were bonded together under the following bonding conditions.
<Bonding conditions>
Pasting device: Product name “DSA840-WS” manufactured by Nitto Seiki Co., Ltd. Pasting speed: 5 mm / min
Pasting pressure: 0.25 MPa
Stage temperature at the time of pasting: 80 ° C
Decompression degree at the time of pasting: 1000 Pa

[Example 3]
A semiconductor device was fabricated in the same manner as in Example 1 except that the semiconductor wafer and the underfill material were bonded together under the following bonding conditions.
<Bonding conditions>
Pasting device: Product name “DSA840-WS” manufactured by Nitto Seiki Co., Ltd. Pasting speed: 5 mm / min
Pasting pressure: 0.25 MPa
Stage temperature at the time of pasting: 80 ° C
Decompression degree when pasting: 100 Pa

[Comparative Example 1]
A semiconductor device was fabricated in the same manner as in Example 1 except that the semiconductor wafer and the underfill material were bonded together under the following bonding conditions.
<Bonding conditions>
Pasting device: Product name “DSA840-WS” manufactured by Nitto Seiki Co., Ltd. Pasting speed: 5 mm / min
Pasting pressure: 0.25 MPa
Stage temperature at the time of pasting: 80 ° C
Decompression degree when pasting: 1100 Pa

[Comparative Example 2]
A semiconductor device was fabricated in the same manner as in Example 1 except that the pressure was not reduced during the bonding of the semiconductor wafer and the underfill material (that is, bonding was performed under atmospheric pressure).

(Measurement of minimum melt viscosity)
The minimum melt viscosity of the underfill material (before thermosetting) was measured. The measurement of the minimum melt viscosity is a value measured by a parallel plate method using a rheometer (manufactured by HAAKE, RS-1). More specifically, the melt viscosity is measured in the range of 60 ° C. to 200 ° C. under the conditions of a gap of 100 μm, a rotating cone diameter of 20 mm, a rotating speed of 10 s ⁻¹ , and a heating rate of 10 ° C./min, and is obtained at that time. The lowest melt viscosity in the range from 100 ° C. to 200 ° C. was defined as the lowest melt viscosity. The results are shown in Table 1.

(Evaluation of chip skipping during dicing)
The number of samples is set to 20, and when the chip jump of the semiconductor chip does not occur during dicing, “◯” is given, and when the chip jump occurs, “X” is given. Retention was evaluated. The results are shown in Table 1.

(Pickup evaluation)
The pick-up property was evaluated by setting the number of samples to 20, and “○” when all the samples could be picked up and “×” when one could not be picked up. The results are shown in Table 1.

(Evaluation of void generation)
Evaluation of the generation of voids is performed by cutting between the semiconductor chip and the underfill material of the semiconductor device manufactured in the example and the comparative example, and the cut surface is an image recognition device (product name “C9597-1” manufactured by Hamamatsu Photonics). ) And calculating the ratio of the total area of the void portion to the area of the underfill material. When the total area of the void portion is 0 to 5% of the area of the underfill material in the observation image of the cut surface, “◯”, when over 5% and below 25%, “△”, when over 25% Was evaluated as “×”. The results are shown in Table 1.

  As can be seen from Table 1, in the manufacturing process of the semiconductor device according to the example, chip skipping during dicing was suppressed, good pickup performance was exhibited, and generation of voids was suppressed. On the other hand, in the manufacturing process of the semiconductor devices of Comparative Examples 1 and 2, although chip fly and pickup evaluation were good, voids were generated. In Comparative Example 1, the depressurization condition exceeds 1000 Pa, and in Comparative Example 2, since the depressurization treatment was not performed, bubbles between the semiconductor wafer and the underfill material were not sufficiently reduced, and eventually voids were formed. It is thought that it occurred. As described above, as a semiconductor device manufacturing process, by bonding the semiconductor wafer and the underfill material under a reduced pressure of 1000 Pa or less, a highly reliable semiconductor device in which generation of voids is suppressed can be manufactured. I understand.

DESCRIPTION OF SYMBOLS 1 Dicing tape 1a Base material 1b Adhesive layer 2 Underfill material 3 Semiconductor wafer 3a Circuit surface of a semiconductor wafer 3b Surface opposite to the circuit surface of a semiconductor wafer 4 Bump (connection member)
5 Semiconductor chip (semiconductor element)
6 adherend 7 conductive material 10 sealing sheet 20 semiconductor device

Claims (5)

A method for manufacturing a semiconductor device comprising an adherend, a semiconductor element electrically connected to the adherend, and an underfill material that fills a space between the adherend and the semiconductor element,
Preparing a sealing sheet comprising a dicing tape and an underfill material laminated on the dicing tape; and
A bonding step of bonding the circuit surface on which the connecting member of the semiconductor wafer is formed and the underfill material of the sealing sheet under a reduced pressure of 1000 Pa or less;
A dicing step of dicing the semiconductor wafer to form the semiconductor element with the underfill material;
A connection step of electrically connecting the semiconductor element and the adherend through the connection member while filling a space between the adherend and the semiconductor element with the underfill material. Production method.   The method for manufacturing a semiconductor device according to claim 1, wherein bubbles are not substantially present at an interface between the semiconductor wafer and the underfill material after the bonding step. The connecting step is a step of bringing the connecting member and the adherend into contact with each other under a temperature α of the following condition (1):
The method for manufacturing a semiconductor device according to claim 1, further comprising: fixing the contact member in contact with the adherend at a temperature β of the following condition (2).
Condition (1): melting point of connecting member−100 ° C. ≦ α <melting point of connecting member Condition (2): melting point of connecting member ≦ β ≦ melting point of connecting member + 100 ° C.   The method for manufacturing a semiconductor device according to claim 1, wherein a minimum melt viscosity at 100 to 200 ° C. of the underfill material before thermosetting is 100 Pa · s or more and 20000 Pa · s or less. The method for manufacturing a semiconductor device according to claim 1, wherein the underfill material before thermosetting has a viscosity at 23 ° C. of 0.01 MPa · s to 100 MPa · s.

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