Shape prediction method, viscous fluid composition design method, viscous fluid, and semiconductor device manufacturing method

Abstract

To provide a method for predicting the shape of a viscous fluid located in an area outside a semiconductor element, a method for designing the composition of a viscous fluid, and a method for manufacturing a viscous fluid and a semiconductor device.SOLUTION: A method for predicting the shape of a viscous fluid includes a first process for identifying the flow speed of the viscous fluid when an object is pressed against the viscous fluid on a substrate, a second process for identifying the viscosity of the viscous fluid in a velocity range including the identified flow speed, and a third process for using the identified viscosity to calculate the shape of a target portion, which is a portion of the viscous fluid located in an outer region of the object when viewed from above.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a shape prediction method, a method for designing a viscous fluid composition, a viscous fluid, and a method for manufacturing a semiconductor device. [Background technology]

[0002] Semiconductor devices are manufactured by mounting a semiconductor element on a substrate such as a lead frame via a viscous fluid. The semiconductor device is manufactured by mounting the semiconductor element so that it is pressed against the viscous fluid placed on the substrate. Patent Document 1 describes a method for simulating the extrusion of a plastic material when the plastic material is supplied from a supply port, using a material model that models the plastic material and a flow path model that models the flow path. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-43545 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above manufacturing method, the viscous fluid may overflow into the region outside the semiconductor element after mounting. The shape of this overflowing portion affects the reliability of the semiconductor device. Therefore, from the viewpoint of improving the reliability of the semiconductor device, it is preferable to be able to predict the shape of the viscous fluid located in the region outside the semiconductor element. [Means for solving the problem]

[0005] According to the present invention, there are provided the following shape prediction method, viscous fluid composition design method, viscous fluid, and semiconductor device manufacturing method. [1] a first process for determining a flow rate of a viscous fluid when an object is pressed against the viscous fluid on a substrate; a second process for determining the viscosity of the viscous fluid in a velocity range including the determined flow velocity; a third process of calculating a shape of a target portion, which is a portion of the viscous fluid located in an outer region of the object in a top view, using the identified viscosity; A method for predicting the shape of a viscous fluid, comprising: [2] In the third process, a shape of a fillet included in the target portion is calculated. The shape prediction method described in [1]. [3] The shape of the fillet includes a height of the fillet in a direction vertical to the base material. The shape prediction method described in [2]. [4] The shape of the fillet includes a length of the fillet in a horizontal direction relative to the base material. The shape prediction method described in [2]. [5] The shape of the fillet includes the horizontal length of the fillet in each region of the edge of the object. The shape prediction method described in [4]. [6] The viscous fluid is a paste or a hot melt agent; A shape prediction method according to any one of [1] to [5]. [7] In the first process, a flow velocity of the viscous fluid is determined using the results of the simulation. A shape prediction method according to any one of [1] to [6]. [8] the simulation is performed using at least one of an initial distribution, a volume, and a viscosity of the viscous fluid, and a movement amount, a movement time, a movement speed, a movement acceleration, and a pressing load when pressing the object; The shape prediction method described in [7]. [9] In the second process, the viscosity is measured by actual measurement. A shape prediction method according to any one of [1] to [8].

[10] The measurement is performed under different conditions depending on the shear rate region. The shape prediction method described in [9].

[11] The actual measurement is In the low shear rate region, a rotational viscometer is used. In the high shear rate region, a capillary viscometer is used. The shape prediction method described in

[10] .

[12] The third process is carried out by a VOF method. A shape prediction method according to any one of [1] to

[11] .

[13] A method for designing a composition of a viscous fluid, comprising adjusting the composition of the viscous fluid based on the shape of a fillet predicted by the shape prediction method according to any one of [1] to

[12] .

[14] A viscous fluid whose composition is adjusted so that the shape of a fillet predicted by the shape prediction method according to any one of [1] to

[12] satisfies predetermined conditions.

[15] Mounting a semiconductor element on the viscous fluid applied to a substrate, A method for manufacturing a semiconductor device, wherein the mounting step is performed under conditions designed so that the shape of the fillet predicted by the shape prediction method described in any one of [1] to

[12] satisfies specified conditions. [Effects of the Invention]

[0006] According to the present invention, in a semiconductor device manufactured by mounting a semiconductor element on a viscous fluid on a substrate, it is possible to predict the shape of the viscous fluid located in an area outside the semiconductor element. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a semiconductor device. [Figure 2] 1A to 1C are cross-sectional views showing a manufacturing process of a semiconductor device. [Figure 3] FIG. 1 is a flowchart of a shape prediction method according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, like components are denoted by like reference numerals, and the description thereof will be omitted as appropriate.

[0009] [Semiconductor device 100] 1 is a schematic diagram of an example of a semiconductor device 100 according to this embodiment. The semiconductor device 100 includes a semiconductor element 10, an adhesive layer 20, and a base material 30.

[0010] The semiconductor element 10 is, for example, a semiconductor package including a semiconductor chip. The semiconductor chip may be, for example, a power semiconductor that converts and controls power, a CMOS image sensor, or an LED (Light Emitting Diode). Specific types of the semiconductor package include a hollow package, a mold array package (MAP), a quad flat package (QFP), a small outline package (SOP), a chip size package (CSP), a quad flat non-leaded package (QFN), a small outline non-leaded package (SON), a ball grid array (BGA), a lead flame ball grid array (LF-BGA), a flip chip ball grid (FC-BGA), a molded array process ball grid (MAP-BGA), an embedded wafer-level ball grid (eWLB), a fan-in type eWLB, and a fan-out type eWLB.

[0011] The adhesive layer 20 is a layer formed by curing a viscous fluid, which will be described later, and fixes the semiconductor element 10 onto the substrate 30. The adhesive layer 20 may be conductive or insulating. The adhesive layer 20 may contain a filler. If the filler is conductive, the adhesive layer 20 will be conductive.

[0012] The substrate 30 is, for example, a wiring board. Examples of wiring boards include a lead frame and a printed circuit board. The semiconductor element 10 is electrically connected to the wiring of the substrate 30 by wire bonding, flip-chip connection, or the like.

[0013] 1, the adhesive layer 20 may include a fillet 21 located in an area outside the semiconductor element 10. This is a portion that is generated when the semiconductor element 10 is mounted on the substrate 30 in the manufacturing process of the semiconductor device 100, which will be described later, and depending on the shape of this portion, it may reduce the reliability of the semiconductor device 100.

[0014] The prediction method according to the present embodiment, which will be described later, can accurately predict the shape of the fillet 21. Furthermore, using the results of the prediction method according to the present embodiment, the physical properties of the viscous fluid that forms the adhesive layer 20 and the mounting conditions when manufacturing the semiconductor device 100 can be designed so as to obtain a desirable shape of the fillet 21.

[0015] [Viscous fluid] The viscous fluid according to this embodiment will be described below. The viscous fluid is, for example, a paste such as a conductive paste or a hot melt agent.

[0016] (Conductive paste) The components of the conductive paste, which is an example of a viscous fluid, will be described below.

[0017] (Conductive particles) The conductive paste contains conductive particles. The conductive particles are not particularly limited as long as they are conductive, but may be, for example, metal particles. The metal particles are preferably silver particles, but may also contain metal particles containing other metals. The metal particles may also be particles whose surfaces are only covered with metal. When the conductive paste according to this embodiment is subjected to a heat treatment, the conductive particles aggregate to form a connected structure, thereby forming an adhesive layer 20 with excellent conductivity and heat dissipation properties.

[0018] The shape of the conductive particles is not particularly limited, but examples thereof include spherical, flake, and scale shapes.

[0019] The average particle size (D50) of the conductive particles is, for example, 0.1 μm or more and 10 μm or less. When the average particle size of the conductive particles is equal to or more than the above-mentioned lower limit, an excessive increase in the specific surface area can be suppressed, and a decrease in thermal conductivity due to contact thermal resistance can be suppressed. Furthermore, when the average particle size of the conductive particles is equal to or less than the above-mentioned upper limit, it is possible to improve the formability of silver particle linked structures between the conductive particles. Furthermore, from the viewpoint of improving the dispensability of the conductive paste, the average particle size (D50) of the conductive particles is more preferably 0.6 μm or more and 2.7 μm or less, and particularly preferably 0.6 μm or more and 2.0 μm or less. The average particle size (D50) of the conductive particles can be measured, for example, using a commercially available laser particle size distribution analyzer.

[0020] The content of the conductive particles in the conductive paste is, for example, 40 parts by mass or more and 90 parts by mass or less, and preferably 50 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the conductive paste. By setting the content at or above the lower limit, it is possible to contribute to improving the thermal conductivity and electrical conductivity of the adhesive layer 20 obtained by heat-treating the conductive paste. On the other hand, by setting the content at or below the upper limit, it is possible to contribute to improving the dispensability (application workability) of the obtained conductive paste and the mechanical strength of the adhesive layer 20 obtained by heat-treating the conductive paste.

[0021] (diluent) The conductive paste preferably contains a diluent to achieve an appropriate viscosity for application to the substrate 30 and filling into fine details. The diluent can be a reactive diluent or a non-reactive solvent. Here, a reactive diluent refers to a polymerizable monomer that hardens upon heat treatment and promotes the aggregation of conductive particles, or, if the conductive paste contains a thermosetting resin as a binder resin, a compound having a reactive group that participates in a crosslinking reaction with the resin. A non-reactive solvent refers to a solvent that does not have a polymerizable or crosslinkable reactive group and that can volatilize upon heat treatment.

[0022] The polymerizable monomer as the reactive diluent may be, for example, one or a combination of two or more selected from glycol monomers, acrylic monomers, epoxy monomers, maleimide monomers, and imide monomers.

[0023] Examples of non-reactive solvents include alcohols such as ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, hexyl alcohol, heptyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, methyl methoxybutanol, α-terpineol, β-terpineol, hexylene glycol, benzyl alcohol, 2-phenylethyl alcohol, isopalmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, and glycerin; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl-2-pentanone), 2-octanone, isopropyl alcohol, methyl methyl ketone, methyl ethyl ketone, methyl ...methyl ketone, methyl methyl methyl methyl ketone, methyl methyl methyl methyl ketone, methyl methyl methyl methyl ketone, methyl methyl methyl methyl methyl ketone, methyl methyl Ketones such as sophorone (3,5,5-trimethyl-2-cyclohexen-1-one) or diisobutyl ketone (2,6-dimethyl-4-heptanone); ethyl acetate, butyl acetate, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octanoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2-diacetoxyethane, tributyl phosphate, tricresyl phosphate or esters such as tripentyl phosphate; ethers such as tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, ethoxyethyl ether, 1,2-bis(2-diethoxy)ethane or 1,2-bis(2-methoxyethoxy)ethane; ester ethers such as 2-(2-butoxyethoxy)ethane acetate; ether alcohols such as 2-(2-methoxyethoxy)ethanol;One or a combination of two or more selected from hydrocarbons such as toluene, xylene, n-paraffin, isoparaffin, dodecylbenzene, turpentine, kerosene, and light oil; nitriles such as acetonitrile and propionitrile; amides such as acetamide and N,N-dimethylformamide; low molecular weight volatile silicone oils, and volatile organic modified silicone oils can be used.

[0024] The content of the diluent in the conductive paste is preferably 3 parts by mass or more, and more preferably 4 parts by mass or more, per 100 parts by mass of the conductive paste. This makes it possible to more effectively improve the ease of application of the conductive paste and the flatness of the resulting adhesive layer 20. On the other hand, the content of the diluent in the conductive paste is preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, per 100 parts by mass of the conductive paste. This makes it possible to suppress dripping during application and improve application workability. It also makes it possible to improve the hardening properties of the conductive paste.

[0025] (thermosetting resin) The conductive paste may contain a thermosetting resin as a binder resin, if necessary, which may be one or a combination of two or more selected from the group consisting of cyanate resins, epoxy resins, resins having two or more radically polymerizable carbon-carbon double bonds in one molecule, allyl resins, and maleimide resins.

[0026] As the epoxy resin used as the thermosetting resin, any monomer, oligomer, or polymer having two or more glycidyl groups in one molecule can be used, and there are no particular limitations on the molecular weight or molecular structure. Examples of epoxy resins used in this embodiment include biphenyl-type epoxy resins; bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, and tetramethylbisphenol F-type epoxy resins; stilbene-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins and cresol novolac-type epoxy resins; multifunctional epoxy resins such as triphenolmethane-type epoxy resins and alkyl-modified triphenolmethane-type epoxy resins; aralkyl-type epoxy resins such as phenol aralkyl-type epoxy resins having a phenylene skeleton and phenol aralkyl-type epoxy resins having a biphenylene skeleton; naphthol-type epoxy resins such as dihydroxynaphthalene-type epoxy resins and epoxy resins obtained by glycidyl etherifying a dihydroxynaphthalene dimer; triazine-nucleus-containing epoxy resins such as triglycidyl isocyanurate and monoallyl diglycidyl isocyanurate; and bridged cyclic hydrocarbon compound-modified phenol-type epoxy resins such as dicyclopentadiene-modified phenol-type epoxy resins. In addition, epoxy resins that can be used include, for example, bisphenol compounds such as bisphenol A, bisphenol F, and biphenol, or derivatives thereof, among compounds containing two or more glycidyl groups per molecule; diols having an alicyclic structure such as hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated biphenol, cyclohexanediol, cyclohexanedimethanol, and cyclohexanediethanol, or derivatives thereof; and bifunctional epoxidized aliphatic diols such as butanediol, hexanediol, octanediol, nonanediol, and decanediol, or derivatives thereof; and trifunctional epoxidized compounds having a trihydroxyphenylmethane skeleton or an aminophenol skeleton. Epoxy resins as thermosetting resins can include one or a combination of two or more selected from the above examples.

[0027] The cyanate resin used as the thermosetting resin is not particularly limited, and examples thereof include 1,3-dicyanatobenzene, 1,4-dicyanatobenzene, 1,3,5-tricyanatobenzene, 1,3-dicyanatonaphthalene, 1,4-dicyanatonaphthalene, 1,6-dicyanatonaphthalene, 1,8-dicyanatonaphthalene, 2,6-dicyanatonaphthalene, 2,7-dicyanatonaphthalene, 1,3,6-tricyanatonaphthalene, 4,4'-dicyanatobiphenyl, bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, 2,2-bis(4-cyanatophenyl)methane, bis(3,5-dimethyl-4-cyanatophenyl)methane, bis( ... The polyfunctional cyanate resin may contain one or more compounds selected from the group consisting of tris(4-cyanatophenyl)propane, 2,2-bis(3,5-dibromo-4-cyanatophenyl)propane, bis(4-cyanatophenyl)ether, bis(4-cyanatophenyl)thioether, bis(4-cyanatophenyl)sulfone, tris(4-cyanatophenyl)phosphite, tris(4-cyanatophenyl)phosphate, cyanates obtained by reacting a novolak resin with a cyanogen halide, and prepolymers having a triazine ring formed by trimerizing the cyanate groups of these polyfunctional cyanate resins. The prepolymers can be obtained by polymerizing the polyfunctional cyanate resin monomers using, for example, an acid such as a mineral acid or a Lewis acid, a base such as a sodium alcoholate or a tertiary amine, or a salt such as sodium carbonate as a catalyst.

[0028] The resin having two or more radically polymerizable carbon-carbon double bonds in one molecule and used as the thermosetting resin may be, for example, a radically polymerizable acrylic resin having two or more (meth)acryloyl groups in one molecule. In this embodiment, the acrylic resin may be a compound having a (meth)acrylic group, such as polyether, polyester, polycarbonate, or poly(meth)acrylate, having a molecular weight of 500 to 10,000. When a resin having two or more radically polymerizable carbon-carbon double bonds in one molecule is used as the thermosetting resin, the conductive paste may contain a polymerization initiator, such as a thermal radical polymerization initiator.

[0029] The allyl resin used as the thermosetting resin can be an allyl ester resin obtained by reacting a dicarboxylic acid, allyl alcohol, and a compound having an allyl group. Specific examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, and hexahydrophthalic acid. The dicarboxylic acid can be one or a combination of two or more of the above specific examples. Specific examples of compounds having an allyl group include polyethers, polyesters, polycarbonates, polyacrylates, polymethacrylates, polybutadienes, and butadiene-acrylonitrile copolymers that have an allyl group. The compounds having an allyl group may be selected from the above specific examples, or may be used in combination of two or more. Specific examples of allyl resins that can be used include polymers of bis(2-propenyl) 1,2-cyclohexanedicarboxylate and propane-1,2-diol.

[0030] The maleimide resin used as the thermosetting resin is not particularly limited, and may be one or a combination of two or more selected from bismaleimide resins such as N,N'-(4,4'-diphenylmethane)bismaleimide, bis(3-ethyl-5-methyl-4-maleimidophenyl)methane, and 2,2-bis[4-(4-maleimidophenoxy)phenyl]propane.

[0031] When a thermosetting resin is blended into the conductive paste of this embodiment, the lower limit of the content of the thermosetting resin is, for example, 1 part by mass or more, preferably 3 parts by mass or more, and more preferably 5 parts by mass or more, per 100 parts by mass of the conductive paste. This improves the handleability of the conductive paste. It also allows the viscosity of the conductive paste to be adjusted to a level appropriate for use. The upper limit of the content of the thermosetting resin is, for example, 15 parts by mass or less, preferably 12 parts by mass or less, and more preferably 10 parts by mass or less, per the entire conductive paste. This improves the balance of various properties of the conductive paste, such as its conductivity and adhesion to the substrate 30.

[0032] (hardening agent) The conductive paste of this embodiment may contain a curing agent. This can improve the curing properties of the conductive paste. As the curing agent, for example, one or a combination of two or more selected from aliphatic amines, aromatic amines, dicyandiamide, dihydrazide compounds, acid anhydrides, and phenolic compounds can be used. Among these, it is particularly preferable to contain at least one of dicyandiamide and phenolic compounds from the viewpoint of improving production stability.

[0033] The dihydrazide compound used as the curing agent may be one or a combination of two or more selected from carboxylic acid dihydrazides such as adipic acid dihydrazide, dodecanoic acid dihydrazide, isophthalic acid dihydrazide, and p-oxybenzoic acid dihydrazide. The acid anhydride used as the curing agent may be one or a combination of two or more selected from phthalic acid anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, dodecenylsuccinic anhydride, a reaction product of maleic anhydride and polybutadiene, a copolymer of maleic anhydride and styrene, and the like.

[0034] The phenol compound used as the curing agent is a compound having two or more phenolic hydroxyl groups in one molecule. The number of phenolic hydroxyl groups in one molecule is more preferably 2 to 5, and particularly preferably 2 or 3. This can more effectively improve the ease of application of the conductive paste, and can form a crosslinked structure upon curing, resulting in excellent properties of the cured product of the conductive paste. The phenol compound may include one or more selected from the group consisting of bisphenols such as bisphenol F, bisphenol A, bisphenol S, tetramethylbisphenol A, tetramethylbisphenol F, tetramethylbisphenol S, dihydroxydiphenyl ether, dihydroxybenzophenone, tetramethylbiphenol, ethylidenebisphenol, methylethylidenebis(methylphenol), cyclohexylidenebisphenol, and biphenol, trifunctional phenols such as tri(hydroxyphenyl)methane and tri(hydroxyphenyl)ethane, and derivatives thereof, and compounds obtained by reacting phenols such as phenol novolac and cresol novolac with formaldehyde, which are mainly binuclear or trinuclear, and derivatives thereof. Among these, bisphenols are more preferred, and bisphenol F is particularly preferred.

[0035] In this embodiment, a phenolic resin (phenolic compound) having a biphenyl skeleton can be used as the resin having a biphenyl skeleton as the curing agent. This can improve the conductivity of the conductive paste and the adhesion to the substrate 30. The structure of the phenolic resin having a biphenyl skeleton is not particularly limited as long as it has a biphenyl skeleton in its molecular structure and two or more phenol groups.

[0036] In this embodiment, the content of the curing agent in the conductive paste is preferably 0.5 parts by mass or more, and more preferably 1.0 parts by mass or more, based on the total amount of the conductive paste. This makes it possible to more effectively improve the curability of the conductive paste. On the other hand, the content of the curing agent in the conductive paste is preferably 10 parts by mass or less, and more preferably 7 parts by mass or less, based on the total amount of the conductive paste. This makes it possible to improve the low thermal expansion and moisture resistance of the adhesive layer 20 formed using the conductive paste.

[0037] (Other ingredients) In addition to the above-mentioned components, the conductive paste may contain various additional components commonly used in the art, as needed. Examples of additional components include, but are not limited to, a silane coupling agent, a curing accelerator, a radical polymerization initiator, a stress reducing agent, an inorganic filler, etc., and these can be selected depending on the desired performance.

[0038] (Method of manufacturing conductive paste) The method for preparing the conductive paste is not particularly limited. For example, the above-mentioned components can be premixed, kneaded using a triple roll mill, and then vacuum degassed to obtain a paste-like composition. The viscosity of the conductive paste can be adjusted depending on the application. The viscosity of the conductive paste can be controlled by adjusting the type of binder resin and diluent used, the amount of each, etc.

[0039] (hot melt agent) The components of a hot melt agent, which is another example of a viscous fluid, are described below. The hot melt agent described below can be used as a viscous fluid at a temperature of, for example, 100°C or higher and 150°C or lower.

[0040] (Resin composition) The hot melt agent includes a resin composition. The resin composition is not particularly limited, but preferably includes a (meth)acrylic resin. The (meth)acrylic resin is preferably a copolymer of a (meth)acrylic acid ester and another monomer, and is preferably a (meth)acrylic resin containing (meth)acrylic acid and its derivatives as the main monomer.

[0041] Examples of (meth)acrylic acid esters that can be used include acrylic acid esters such as methyl acrylate and ethyl acrylate, and methacrylic acid esters such as methyl methacrylate and ethyl methacrylate. Examples of other monomers that can be used include acrylic acid, methacrylic acid, acrylonitrile, and acrylamide.

[0042] Furthermore, the (meth)acrylic resin is preferably a (meth)acrylic acid ester copolymer having an epoxy group, a hydroxyl group, a carboxyl group, a nitrile group, or the like. This can further improve adhesion. Specific examples of compounds having such functional groups include glycidyl (meth)acrylate having a glycidyl ether group, hydroxy (meth)acrylate having a hydroxyl group, carboxy (meth)acrylate having a carboxyl group, and (meth)acrylonitrile having a nitrile group.

[0043] Among these, it is particularly preferable to use a (meth)acrylic acid ester copolymer containing a monomer unit having a carboxyl group, which further accelerates the curing of the hot melt agent and makes the adhesion stronger.

[0044] The content of the (meth)acrylic acid ester copolymer containing a monomer unit having a carboxyl group is, for example, preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, relative to 100 parts by mass of the (meth)acrylic resin. From the viewpoint of further improving the storage stability of the hot melt agent, the content of the compound having a carboxyl group is, for example, preferably 10 parts by mass or less, more preferably 5 parts by mass or less, relative to the total (meth)acrylic resin.

[0045] The weight-average molecular weight of the (meth)acrylic resin is, for example, preferably 100,000 or more and 1,300,000 or less, and more preferably 150,000 or more and 1,000,000 or less. By making the weight-average molecular weight equal to or more than the lower limit, the film-forming properties of the hot-melt agent can be further improved, and by making the weight-average molecular weight equal to or less than the upper limit, it is possible to ensure fluidity during adhesion.

[0046] The content of the (meth)acrylic resin relative to 100 parts by mass of the resin composition is preferably 10 parts by mass or more, more preferably 25 parts by mass or more. This leads to improved adhesiveness of the hot melt agent. The content of the (meth)acrylic resin relative to the entire resin composition is preferably 50 parts by mass or less, more preferably 40 parts by mass or less. This leads to improved workability.

[0047] The weight-average molecular weight of the (meth)acrylic resin can be measured, for example, by gel permeation chromatography (GPC). Examples of measurement conditions include a high-speed GPC SC-8020 device manufactured by Tosoh Corporation, a TSK-GEL GMHXL-L column, a temperature of 40°C, and tetrahydrofuran as the solvent.

[0048] The resin composition may further contain a thermosetting resin. It is particularly preferable for the thermosetting resin to contain an epoxy resin. The epoxy resin refers to any one of a monomer, oligomer, and polymer having an epoxy group. Specific examples of epoxy resins include novolac epoxy resins such as phenol novolac epoxy resins and cresol novolac epoxy resins; bisphenol epoxy resins such as bisphenol A epoxy resins and bisphenol F epoxy resins; hydroquinone epoxy resins; biphenyl epoxy resins; stilbene epoxy resins; triphenolmethane epoxy resins; triazine nucleus-containing epoxy resins; dicyclopentadiene-modified phenol epoxy resins; naphthol epoxy resins; and aralkyl epoxy resins such as phenol aralkyl epoxy resins having a phenylene and / or biphenylene skeleton and naphthol aralkyl epoxy resins having a phenylene and / or biphenylene skeleton.

[0049] The content of the epoxy resin is not particularly limited, but is preferably 1 part by mass or more and 15 parts by mass or less, and particularly preferably 5 parts by mass or more and 10 parts by mass or less, per 100 parts by mass of the hot melt agent.

[0050] (hardening agent) The hot melt agent may further contain a curing agent. Specific examples of the curing agent include aliphatic polyamines such as diethylenetriamine, triethylenetetramine, and metaxylenediamine, aromatic polyamines such as diaminodiphenylmethane, m-phenylenediamine, and diaminodiphenylsulfone, amine-based curing agents such as polyamine compounds containing dicyandiamide and organic acid dihydrazides, acid anhydride-based curing agents such as aliphatic acid anhydrides such as hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride, and aromatic acid anhydrides such as tritomellitic anhydride, pyromellitic anhydride, and benzophenonetetracarboxylic acid, phenol novolac resins, cresol novolac resins, phenol aralkyl (containing phenylene or biphenylene skeletons) resins, naphthol aralkyl (containing phenylene or biphenylene skeletons) resins, triphenolmethane resins, and dicyclopentadiene-type phenols. One or a combination of two or more selected from the group consisting of phenolic curing agents such as phenol resins, bis(mono- or di-t-butylphenol)propane, methylenebis(2-propenyl)phenol, propylenebis(2-propenyl)phenol, bis[(2-propenyloxy)phenyl]methane, bis[(2-propenyloxy)phenyl]propane, 4,4'-(1-methylethylidene)bis[2-(2-propenyl)phenol], 4,4'-(1-methylethylidene)bis[2-(1-phenylethyl)phenol], 4,4'-(1-methylethylidene)bis[2-methyl-6-hydroxymethylphenol], 4,4'-(1-methylethylidene)bis[2-methyl-6-(2-propenyl)phenol], and 4,4'-(1-methyltetradecylidene)bisphenol can be used.

[0051] The content of the curing agent is not particularly limited, but is preferably 0.5 to 10 parts by mass, particularly preferably 1 to 7 parts by mass, per 100 parts by mass of the hot melt agent.

[0052] (Other ingredients) In addition to the above-mentioned components, the hot melt agent may contain various additional components commonly used in the art, as needed. The additional components include, but are not limited to, a silane coupling agent, a curing accelerator, a radical polymerization initiator, a stress reducing agent, an inorganic filler, etc., and can be selected depending on the desired performance.

[0053] (Hot melt agent manufacturing method) The hot melt agent can be obtained by dissolving the above-mentioned resin composition in a solvent such as methyl ethyl ketone, acetone, toluene, or dimethyl formaldehyde.

[0054] [Method of manufacturing the semiconductor device 100] Next, a method for manufacturing the semiconductor device 100 according to this embodiment will be described.

[0055] The manufacturing method of the semiconductor device 100 according to this embodiment includes a preparation process for preparing a substrate 30, an application process for applying a viscous fluid (adhesive layer 20) onto the substrate 30, and a mounting process for pressurizing (mounting) the semiconductor element 10 onto the viscous fluid.

[0056] (preparation process) The base material 30 prepared in the preparation step is, for example, a general lead frame or a printed circuit board.

[0057] (Coating process) In the application step, a viscous fluid is applied to the substrate 30 at a position where the semiconductor element 10 is to be mounted. The viscous fluid is applied by, for example, a screen printing method. The viscous fluid is applied to a thickness of, for example, 50 μm or more and 500 μm or less. If the viscous fluid is a hot melt agent, it is heated to, for example, 100° C. or more and 150° C. or less.

[0058] (mounting process) In the mounting step, the semiconductor element 10 is placed on the viscous fluid applied in the application step, and pressure is applied from above to fix the semiconductor element 10. The pressure load is preferably, for example, 1 gf to 100 kgf, and more preferably 50 gf to 500 gf. The overall time for the mounting step is preferably, for example, 0.1 ms to 600 s, and more preferably 50 ms to 500 ms. At this time, a heat treatment may be further performed to harden the viscous fluid. The heating temperature is set appropriately depending on the viscous fluid.

[0059] In the mounting process, the viscous fluid is cured to form the adhesive layer 20, but the viscous fluid may overflow into the area outside the semiconductor element 10, forming the adhesive layer 20. The shape of the viscous fluid in the area outside the semiconductor element 10 can be predicted by a prediction method described below.

[0060] [Prediction method] Next, a shape prediction method according to this embodiment will be described. FIG. 3 is a flowchart of the prediction method. The prediction method according to this embodiment includes a first process of identifying the flow speed of the viscous fluid when an object (semiconductor element 10) is pressed against the viscous fluid on the substrate 30, a second process of identifying the viscosity of the viscous fluid in a velocity range including the identified flow speed, and a third process of using the identified viscosity to calculate the shape of a target portion (fillet 21 in FIG. 1, as an example) of the viscous fluid located in an area outside the object when viewed from above. Each step will be described below.

[0061] (First process) In the first process, when an object is pressed against the viscous fluid on the substrate 30, the flow velocity in each region as the viscous fluid spreads over the underside of the semiconductor element 10 is identified by simulation. The flow velocity is identified by simulation such as the finite element method, and a fluid model that models the viscous fluid and a flow path model that models the fluid path using the shapes of the substrate 30 and the semiconductor element 10 and the distance between them are input into a computer. The fluid model may further define the viscosity, specific heat, thermal conductivity, and the like according to the shear rate of the viscous fluid. The fluid model may also define the initial distribution of the viscous fluid.

[0062] The flow velocity determined in the first process includes three-dimensional components.

[0063] An example of the boundary conditions used in the simulation of the first process is the surface where the viscous fluid contacts the substrate 30 or the semiconductor element 10, and the magnitude of the load applied to the semiconductor element 10.

[0064] The simulation in the first process is performed using, for example, the initial distribution, volume, and viscosity of the viscous fluid, as well as at least one of the movement amount, movement time, movement speed, movement acceleration, and pressing load when pressing an object. More preferably, the simulation is performed using at least one of the initial distribution of the viscous fluid, and the movement amount and movement time when pressing the object. Specifically, for example, the simulation is performed by determining the flow rate of the viscous fluid in each region per unit time. In this case, first, the flow rate of the viscous fluid in each region at the start of mounting is determined. Next, the determined flow rate is used to determine the region of the viscous fluid after the unit time has elapsed. This process is repeated to determine the flow rate in each region until the viscous fluid spreads over the entire underside of the semiconductor element 10.

[0065] In the first process, the flow velocity of the viscous fluid in a specific portion may be determined, for example, only at one location in the outer region of the semiconductor element 10. Preferably, two or more specific portions are determined. It is also preferable to determine the flow velocity of the viscous fluid in one or more regions each in the inner and outer regions of the semiconductor element 10. The flow velocity of the viscous fluid in the inner region of the semiconductor element 10 may be determined as any one of the maximum flow velocity, the average flow velocity, or the relationship between the distance from the boundary with the outer region and the flow velocity. The flow velocity of the viscous fluid in the outer region of the semiconductor element 10 may be determined as any one of the maximum flow velocity, the average flow velocity, or the relationship between the distance from the boundary with the inner region and the flow velocity.

[0066] (Second process) In the second process, the viscosity of the viscous fluid in a velocity range including the flow velocity identified in the first process is identified. The second process is performed, for example, by storing in advance the viscosity corresponding to the shear rate (flow velocity) of the viscous fluid and reading out the viscosity corresponding to the flow velocity identified in the first process. In the second process, it is preferable to identify the viscosity of the viscous fluid in a velocity range including the flow velocity in each region identified in the first process.

[0067] The viscosity specified in the second process may be a viscosity in a speed range that includes the flow velocity of one region, but it is preferable to specify a viscosity in a speed range that includes the flow velocity of two or more regions. In this case, it is more preferable that the two or more regions include one or more regions inside the semiconductor element 10 and one or more regions outside the semiconductor element 10. In addition, when the ratio of the flow velocity of the viscous fluid in the region inside the semiconductor element 10 to the flow velocity of the viscous fluid in the region outside the semiconductor element 10 exceeds 10, it is more preferable to specify a viscosity in a speed range that includes one or more flow velocities that are more than two times but less than 10 times the smaller flow velocity.

[0068] Alternatively, the second process may be performed by actual measurement. The second process may be performed by measuring the viscosity using a viscometer such as a rotational viscometer or a capillary viscometer. The measured viscosity is preferably 1 mPa·s or more and 10 MPa·s or less. When the viscosity is in this range, the accuracy of the prediction result is improved.

[0069] Furthermore, when the second process is performed by actual measurement, the actual measurement may be performed under different conditions depending on the shear rate region. For example, in the low shear rate region, the actual measurement may be performed using a rotational viscometer such as a parallel plate type, a cone-plate type, a double cylinder type, or a short cylinder type. For the high shear rate region, the actual measurement may be performed using a capillary viscometer such as a constant load extrusion type, a constant speed extrusion type, a single tube type, a double tube type, a triple tube type, a cylindrical type, or a rectangular type. Examples of rotational viscometers include the ARES-G2 rheometer (manufactured by TA Instruments) and the MCR302 rheometer (manufactured by Anton Paar). Examples of capillary viscometers include the CFT-500EX constant test force extrusion type capillary rheometer (manufactured by Shimadzu Corporation) and the Capillograph 583 (manufactured by Toyo Seiki Co., Ltd.). The low shear rate region may be, for example, a 1 μs -1 More than 1ks -1 The high shear rate region is in the range of 1 s -1 More than 10Ms -1 The range is as follows:

[0070] [Third Process] In the third process, the shape of a target portion, which is a portion of the viscous fluid located outside the object (semiconductor element 10) in a top view, is calculated by simulation. Specifically, for example, the VOF method can be used for the simulation. The simulation in the third process is performed using the viscosity determined in the second process. In this case, if a flow velocity distribution occurs in the viscous fluid in the first process, a viscosity distribution may occur in the viscous fluid according to this distribution.

[0071] Furthermore, similar to the simulation of the first process, in the simulation of the third process, the surfaces of the substrate and the semiconductor element 10 that are in contact with the viscous fluid and the magnitude of the load applied to the semiconductor element 10 may be defined as boundary conditions. Furthermore, in the simulation of the third process, the movement of the semiconductor element 10 may be defined using at least one of the position, velocity, acceleration, and reaction force of the semiconductor element 10.

[0072] Furthermore, the simulation in the third process is preferably performed by a coupled analysis in which the speed of the object (semiconductor element 10) pressed against the viscous fluid and the load with which the object is pressed against the viscous fluid are defined.

[0073] The shape calculated in the third process is, for example, the shape of the fillet 21 (see FIG. 1) included in the target part. Specifically, it may include the length of the fillet 21 in the horizontal direction relative to the base material 30 (W1 in FIG. 1), or the height of the fillet 21 in the vertical direction relative to the base material 30 (W2 in FIG. 1).

[0074] The shape calculated in the third process may also include the shape of the fillet 21 in each region of the edge of the object (semiconductor element 10). For example, it may include the length of the fillet 21 in the horizontal direction of the substrate over the entire edge of the object.

[0075] As described above, according to the prediction method of this embodiment, the shape of the viscous fluid in the region outside the semiconductor element 10 is predicted by a simulation using the viscosity at a flow velocity identified by the simulation. Therefore, even if the viscous fluid is a non-Newtonian fluid in which the shear stress of the flow is not proportional to the velocity gradient of the flow, the shape can be predicted with high accuracy because the simulation is performed using the viscosity for each velocity region.

[0076] [Method for designing the composition of a viscous fluid using the prediction method according to this embodiment, and the viscous fluid] Furthermore, the prediction method according to this embodiment can be used in the production of viscous fluids. As described above, the viscosity of viscous fluids such as conductive pastes and hot melt agents according to the shear rate can be controlled by adjusting the types and amounts of each component.

[0077] Therefore, the composition of the viscous fluid can be designed by first repeating the above-described prediction method while changing the components of the viscous fluid to identify the components of the viscous fluid that favorably predict the shape of the viscous fluid (fillet 21) in the region outside the semiconductor element 10. Furthermore, the desired viscous fluid can be obtained by adjusting the viscous fluid to the identified components.

[0078] [Method for manufacturing semiconductor device 100 using the prediction method according to this embodiment] Furthermore, the prediction method according to this embodiment can be used in the manufacture of viscous fluids. As described above, the prediction method according to this embodiment is performed by a simulation in which the mounting conditions (pressure load and pressure time) are defined. By performing the prediction method according to this embodiment under a plurality of mounting conditions, it is possible to identify the mounting conditions under which the shape of the viscous fluid (fillet 21) in the region outside the semiconductor element 10 satisfies predetermined conditions. Then, by manufacturing the semiconductor device 100 using the identified mounting conditions and the viscous fluid used at that time, it is possible to manufacture a semiconductor device 100 with an appropriate fillet shape and excellent reliability.

[0079] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations can also be adopted. [Explanation of symbols]

[0080] 100 Semiconductor device 10 Semiconductor elements 20 Adhesive layer 30 Base material

Claims

1. a first process for determining a flow rate of a viscous fluid when an object is pressed against the viscous fluid on a substrate; a second process for determining the viscosity of the viscous fluid in a velocity range including the determined flow velocity; a third process of calculating a shape of a target portion, which is a portion of the viscous fluid located in an outer region of the object in a top view, using the identified viscosity; A method for predicting the shape of a viscous fluid, comprising:

2. In the third process, a shape of a fillet included in the target portion is calculated. The method for predicting a shape according to claim 1 .

3. The shape of the fillet includes a height of the fillet in a direction vertical to the base material. The method for predicting a shape according to claim 2 .

4. The shape of the fillet includes a length of the fillet in a horizontal direction relative to the base material. The method for predicting a shape according to claim 2 .

5. The shape of the fillet includes the horizontal length of the fillet in each region of the edge of the object. The shape prediction method according to claim 4 .

6. The viscous fluid is a paste or a hot melt agent; The shape prediction method according to any one of claims 1 to 5.

7. In the first process, a flow velocity of the viscous fluid is identified using the results of the simulation. The shape prediction method according to any one of claims 1 to 5.

8. the simulation is performed using at least one of an initial distribution, a volume, and a viscosity of the viscous fluid, and a movement amount, a movement time, a movement speed, a movement acceleration, and a pressing load when pressing the object; The method for predicting a shape according to claim 7 .

9. In the second process, the viscosity is measured by actual measurement. The shape prediction method according to any one of claims 1 to 5.

10. The measurement is performed under different conditions depending on the shear rate region. The method for predicting a shape according to claim 9.

11. The actual measurement is In the low shear rate region, a rotational viscometer is used. In the high shear rate region, a capillary viscometer is used. The method for predicting a shape according to claim 10.

12. The third process is carried out by a VOF method. The shape prediction method according to any one of claims 1 to 5.

13. A method for designing a composition of a viscous fluid, comprising adjusting the composition of the viscous fluid based on the shape of a fillet predicted by the shape prediction method according to any one of claims 1 to 5.

14. A viscous fluid whose composition is adjusted so that the shape of a fillet predicted by the shape prediction method according to any one of claims 1 to 5 satisfies predetermined conditions.

15. Mounting a semiconductor element on the viscous fluid applied to a substrate, 6. A method for manufacturing a semiconductor device, wherein the mounting step is performed under conditions designed so that the shape of the fillet predicted by the shape prediction method according to claim 1 satisfies predetermined conditions.

Images