JP2001007258A - Sheet for sealing semiconductor element, semiconductor device and manufacture thereof using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for sealing semiconductor element, which corresponds to the thinning of a package, which can reduce excess resin, and which can obtain a semiconductor device superior in heat transmission. SOLUTION: In a semiconductor element sealing sheet, a resin composition layer 2 constituted of epoxy resin composition containing (A) epoxy resin, (B) hardener, and (C) micro capsule containing curing accelerator which has core/ shell structure where a core part constituted of curing accelerator is coated with a shell constituted of thermoplastic resin components, is formed on a base material face constituted of copper foil 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element sealing sheet used for sealing a semiconductor element, a method of manufacturing a semiconductor device using the same, and a semiconductor device, and more particularly, to a semiconductor device. The present invention relates to a semiconductor device.

[0002]

2. Description of the Related Art Conventionally, a resin-sealed semiconductor device is generally manufactured by resin-sealing a semiconductor element by a transfer molding method, or by resin-sealing by a potting method using a liquid resin. You.

In the transfer molding method, a tablet made of an epoxy resin composition containing an epoxy resin, a curing agent and an inorganic filler as main components is heated and melted, and injected into a mold using a low-pressure transfer molding machine. high temperature·
High pressure state (160 ~ 180 ℃ × 70 ~ 100kg / cm
^This is a method in which the semiconductor element is sealed with a resin by molding in step ² ) and curing the epoxy resin composition. FIG. 7 shows an example of a semiconductor device obtained by this transfer molding method. That is, in this semiconductor device, a semiconductor element 22 is mounted on a die pad 6, and the semiconductor element 22 and the lead frame 8 are connected by a bonding wire 9 such as gold. It is sealed.

In the transfer molding method, a semiconductor element is completely covered with an epoxy resin composition and sealed.
Further, since the resin-encapsulated semiconductor device obtained is molded in a pressurized state, the reliability of the obtained resin-encapsulated semiconductor device is excellent, and the appearance of the package is good. Therefore, at present, most resin-encapsulated semiconductor devices are manufactured by this transfer molding method. By the way, in recent years, semiconductor devices have become thinner and smaller, and the outer shape of a package structure obtained by the transfer molding method is becoming smaller. On the other hand, semiconductor elements to be sealed are increasing in size. For this reason, the gap in which the epoxy resin composition flows in the mold is reduced, and this causes a failure in the flow of the gold wire and a failure in which the die pad on which the semiconductor element is mounted is inclined (die pad shift). It is the present situation that causes. The thickness of a semiconductor device manufactured by the transfer molding method is usually about 3 mm, and the thickness of about 1.0 to 1.4 mm is the limit even in a field where thinning is required. . For example, a semiconductor device incorporated in an IC card is required to be thinner, and the transfer-molded semiconductor device is too thick to meet these requirements.

On the other hand, the potting method using a liquid resin is a method in which a liquid resin is dropped on a semiconductor element with a dispenser, and after-curing, the resin is sealed. One example of a semiconductor device obtained by this potting method is shown in FIGS. The resin-encapsulated semiconductor device shown in FIG. 8 is a semiconductor device in a form called COB (chip-on-board).
Is mounted, and one surface on the side on which the semiconductor element 22 is mounted is resin-sealed with the sealing resin layer 13. The resin-encapsulated semiconductor device shown in FIG.
This is a semiconductor device in a form called (tape automated bonding), in which one surface of a semiconductor element 22 provided with a lead 16 is resin-sealed with a sealing resin layer 14. Further, in the resin-encapsulated semiconductor device shown in FIG. 10, a semiconductor element 22 is mounted on a substrate 18,
This is a semiconductor device in which the mounting surface side of the semiconductor element 22 is resin-sealed with the sealing resin layer 17, and the thickness is usually 0.5 mm.
It is designed below.

[0006]

However, in the potting method using the liquid resin, a swelling occurs on the resin surface due to the surface tension of the dropped liquid resin. To completely seal the semiconductor device with a resin, it is necessary to drop excess liquid resin. In this case, the above-mentioned swell is further increased, and is a great barrier to the reduction in the thickness of the package. In addition, there is no uniformity in the shape of the obtained semiconductor device, and the thickness and sealing area vary greatly,
This is one factor that hinders automation of the mounting process.

As described above, in the potting method using the above liquid resin, it is difficult to adjust the amount of the resin, it is difficult to reduce the thickness, and when a dispenser is set in order to reduce the surplus resin, unfilled defects may occur. It happens frequently.
Therefore, for example, it has been difficult to use it in a field where thinness is required, such as a semiconductor device for an IC card.

[0008] As described above, even if a reduction in thickness is intended, the conventional sealing method has a limit because many problems occur.
Further, as described above, when sealing is performed only with the resin, there is a concern about the strength of a thin package. further,
When these semiconductor devices are used, there is a problem in that reliability is reduced due to heat generation. Therefore, development of a device having excellent heat dissipation is desired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a sheet for encapsulating a semiconductor element having excellent thermal conductivity, capable of coping with a reduction in the thickness of a package, reducing the generation of excess resin. It is an object of the present invention to provide a method for manufacturing a semiconductor device using the same and a semiconductor device.

[0010]

Means for Solving the Problems To achieve the above object, the present invention provides the following (A)
A first object of the present invention is to provide a semiconductor element sealing sheet on which a resin composition layer made of an epoxy resin composition containing components (C) to (C) is formed. (A) Epoxy resin. (B) a curing agent. (C) A hardening accelerator-containing microcapsule having a core / shell structure in which a core made of a hardening accelerator is covered with a shell made of a thermoplastic resin.

A step of disposing the semiconductor element encapsulating sheet on the semiconductor element in a state where the resin composition layer of the semiconductor element encapsulating sheet and the semiconductor element face each other; A step of bonding the element sealing sheet, a step of heating and melting the resin composition layer of the semiconductor element sealing sheet, and a step of curing the resin composition layer in the molten state to resin seal the semiconductor element. A method for manufacturing a semiconductor device having the above is a second gist.

Further, in the semiconductor device obtained by the method for manufacturing a semiconductor device, one surface of the semiconductor element is resin-encapsulated with a cured body made of an epoxy resin composition containing the components (A) to (C). A third aspect is a semiconductor device in which a copper foil is provided on the surface of the cured body.

That is, in the sheet for encapsulating a semiconductor element of the present invention, a resin composition layer composed of an epoxy resin composition containing microcapsules containing a special curing accelerator is formed on one surface of a copper foil. For this reason, at the time of forming the resin composition layer, a curing reaction does not occur even after a heating step, so that a desired uncured resin composition layer can be easily formed.

Further, after arranging the sheet with the semiconductor element and the resin composition layer of the sheet for encapsulating the semiconductor element facing each other, the semiconductor element and the sheet for encapsulating the semiconductor element are adhered to each other. The resin composition layer is heated and melted. Then, the semiconductor device can be easily manufactured by curing the resin composition layer in the molten state. At this time, the resin composition in the molten state can be held without causing the curing reaction to proceed during the heating and melting, and the sealing resin layer can be formed to have a desired thickness. Therefore, a thin semiconductor device having a small thickness can be obtained. Moreover, a copper foil is provided on one side of the obtained semiconductor device, and as a result, a semiconductor element is placed on one side and a copper foil is placed on the other side with the sealing resin layer interposed therebetween. Also excellent ones are obtained. Since the package has excellent thermal conductivity due to the installation of the copper foil, heat generated inside the semiconductor device can be effectively released to the outside.

[0015]

Next, embodiments of the present invention will be described in detail.

The semiconductor element encapsulating sheet of the present invention is shown in FIG.
As shown in FIG. 1, a sheet having a configuration in which a resin composition layer 2 made of an epoxy resin composition is formed on one surface of a copper foil 1. Resin composition layer 2 composed of the above epoxy resin composition
Is a thermosetting resin composition layer in an uncured state, and the uncured state means a state in which the resin composition is not completely cured, and also includes a semi-cured state.

The copper foil 1 is made of another metal foil material, for example,
It has excellent thermal conductivity compared to 42 nickel-iron alloy (42 alloy), stainless steel, aluminum and the like, and its thermal conductivity is 0.94 cal / cm · sec · ° C. By the way, 4
0.032 cal / cm for 2 nickel-iron alloy (42 alloy)
・ Sec ・ ℃, 0.56 cal / cm ・ sec for aluminum
° C, 0.76 cal / cmsec for gold, 0.0 for polymer
016 cal / cm · sec · ° C. The measurement of the thermal conductivity was performed by the unsteady hot wire method.

The epoxy resin composition serving as the material for forming the resin composition layer 2 formed on one surface of the copper foil 1 includes an epoxy resin (A component), a curing agent (B component), and a special curing accelerator. It can be obtained using microcapsules (component C) and shows a solid at room temperature. In addition, the said normal temperature is 25 degreeC
It is.

The epoxy resin (component A) is not particularly limited as long as it is solid at room temperature, and is conventionally known, for example, biphenyl epoxy resin, cresol novolak epoxy resin, bisphenol epoxy resin, hydroquinone epoxy resin. An epoxy resin or the like is used, and it is preferable to use a low-viscosity resin having good wettability when melted. These may be used alone or in combination of two or more. As a specific example of a more preferred epoxy resin,
An epoxy resin having a structure represented by the following general formulas (1), (2), and (3) is given.

[0020]

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[0021]

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[0022]

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The epoxy resin having a structure represented by the above formulas (1) to (3) preferably has a melting point of 50 to 150 ° C.

The curing agent (component B) used together with the epoxy resin (component A) is not particularly limited, and various curing agents generally used, for example, phenol resin, methylhexahydrophthalic anhydride, etc. Acid anhydride-based curing agents are exemplified, and among them, phenol resins are preferably used. As the phenol resin, phenol novolak, cresol novolak and the like are used, and it is particularly preferable to use a resin having a low viscosity. Among them, it is preferable to use those having a hydroxyl equivalent of 80 to 120 g / eq and a softening point of 80C or lower. More preferably, the hydroxyl equivalent is 90 to 110 g / eq, and the softening point is 50 to 70 ° C.
It is. Particularly preferred is a hydroxyl equivalent of 100 to 110 g /
eq, softening point 55-65 ° C.

The epoxy resin (A component) and the curing agent (B
When a phenol resin is used as a curing agent, the mixing ratio of the component) is preferably set such that the hydroxyl group equivalent in the phenol resin is in the range of 0.5 to 1.6 with respect to 1 equivalent of the epoxy group in the epoxy resin. . More preferably 0.8 to
1.2.

A special hardening accelerator-containing microcapsule used together with the above components A and B (component C)
Is a microcapsule having a core / shell structure in which a core made of a curing accelerator is covered with a shell made of a thermoplastic resin.

The curing accelerator included in the core is not particularly limited, and a conventionally known curing accelerator can be used. In this case, those having a liquid state at normal temperature are preferred from the viewpoint of workability in preparing the microcapsules and characteristics of the obtained microcapsules. The term “liquid at room temperature” includes not only the case where the properties of the curing accelerator itself are liquid at room temperature, but also those which are solid at room temperature but are dissolved or dispersed in any organic solvent or the like to form a liquid.

Examples of the curing accelerator include amine, imidazole, phosphorus, boron, and phosphorus-boron curing accelerators. Specifically, alkyl-substituted guanidines such as ethylguanidine, trimethylguanidine, phenylguanidine, diphenylguanidine, and the like, 3- (3,4-dichlorophenyl)-
3-substituted phenyl-1,1-dimethylureas such as 1,1-dimethylurea, 3-phenyl-1,1-dimethylurea, 3- (4-chlorophenyl) -1,1-dimethylurea, 2-methyl Imidazolines such as imidazoline, 2-phenylimidazoline, 2-undecylimidazoline and 2-heptadecylimidazoline; monoaminopyridines such as 2-aminopyridine; N, N-dimethyl-N- (2
-Hydroxy-3-allyloxypropyl) amine-N '
-Amine imides such as lactoimide, ethyl phosphine, propyl phosphine, butyl phosphine, phenyl phosphine, trimethyl phosphine, triethyl phosphine, tributyl phosphine, trioctyl phosphine, triphenyl phosphine, tricyclohexyl phosphine, triphenyl phosphine / triphenyl borane complex, Organophosphorus compounds such as tetraphenylphosphonium tetraphenylborate; diazabicycloalkenes such as 1,8-diazabicyclo [5,4,0] undecene-7 and 1,5-diazabicyclo (4,3,0) nonene-5 And the like. Among them, an organic phosphorus compound such as triphenylphosphine and an imidazole compound are preferably used from the viewpoint of easy preparation and easy handling of the hardening agent-containing microcapsules. These may be used alone or in combination of two or more.

The organic solvent that can be included in the shell portion (wall film) of the microcapsule is not particularly limited as long as it is liquid at ordinary temperature, but at least does not dissolve the shell portion (wall film). You need to choose one. Specifically, ethyl acetate, methyl ethyl ketone,
In addition to organic solvents such as acetone, methylene chloride, xylene, toluene and tetrahydrofuran, oils such as phenylxylylethane and dialkylnaphthalene can be used.

Examples of the thermoplastic resin forming the shell portion (wall film) include polyurea, polyurethane, amino resin, and acrylic resin. Above all, polyurea is preferred in consideration of the stability during storage, the ease of breaking of the shell during molding of the cured product, and the like.

As the polyurea, a polymer having a repeating unit represented by the following general formula (4) as a main component is particularly preferable.

[0032]

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As described above, in equation (4), R ₁ ,
R ₂ is a hydrogen atom or a monovalent organic group;
Is a divalent organic group.

The polymer having the repeating unit represented by the above formula (4) as a main component is obtained, for example, by a polyaddition reaction between a polyvalent isocyanate and a polyvalent amine.
Alternatively, it is obtained by reacting a polyvalent isocyanate with water.

The polyvalent isocyanate may be any compound having two or more isocyanate groups in the molecule. Specific examples thereof include m-phenylene diisocyanate, p-phenylene diisocyanate, and 2,4-tolylene diisocyanate. 2,6-tolylene diisocyanate, naphthalene-1,4-diisocyanate, diphenylmethane-4,4'-diisocyanate, 3,3'-dimethoxy-4,4'-biphenyl diisocyanate,
3,3'-dimethyldiphenylmethane-4,4'-diisocyanate, xylylene-1,4-diisocyanate, 4,4'-diphenylpropane diisocyanate,
Trimethylene diisocyanate, hexamethylene diisocyanate, propylene-1,2-diisocyanate,
Butylene-1,2-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-
Diisocyanates such as 1,4-diisocyanate, p
Phenylenediisothiocyanate, xylylene-1,
Triisocyanates such as 4-diisothiocyanate and ethylidene diisothiocyanate; tetraisocyanates such as 4,4'-dimethyldiphenylmethane-2,2 ', 5,5'-tetraisocyanate; hexamethylene diisocyanate and hexanetriol; Addenda,
Adducts of 2,4-tolylene diisocyanate with prenz catechol, adducts of tolylene diisocyanate and hexanetriol, adducts of tolylene diisocyanate and trimethylolpropane, adducts of xylylene diisocyanate and trimethylolpropane, hexa Like adducts of methylene diisocyanate and trimethylolpropane, trimers of aliphatic polyvalent isocyanates such as triphenyldimethylenetriisocyanate, tetraphenyltrimethylenetetraisocyanate, pentaphenyltetramethylenepentaisocyanate, lysine isocyanate, and hexamethylene diisocyanate. And isocyanate prepolymers. These may be used alone or in combination of two or more.

Among the above polyvalent isocyanates, adducts of tolylene diisocyanate and trimethylolpropane and adducts of xylylene diisocyanate and trimethylolpropane are preferable from the viewpoint of film forming property and mechanical strength when preparing microcapsules. It is preferable to use an isocyanate prepolymer represented by polymethylene polyphenyl isocyanate such as triphenyl dimethylene triisocyanate.

On the other hand, the polyvalent amines to be reacted with the above-mentioned polyvalent isocyanates may be compounds having two or more amino groups in the molecule, and specifically, diethylenetriamine, triethylenetetramine, tetraethylenepentamine. Min, 1,6-hexamethylenediamine, 1,8
-Octamethylenediamine, 1,12-dodecamethylenediamine, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, menthanediamine, bis (4-amino-3-methylcyclohexyl) methane, isophoronediamine, 1,3
-Diaminocyclohexane, spiroacetal diamine and the like. These may be used alone or in combination of two or more.

In the reaction between the polyvalent isocyanate and water, first, an amine is formed by hydrolysis of the polyvalent isocyanate, and this amine reacts with an unreacted isocyanate group (so-called self-polyaddition reaction). Thereby, a polymer having the repeating unit represented by the general formula (4) as a main component is formed.

The curing accelerator-containing microcapsules are
There is no particular limitation as long as it can be microencapsulated, and it can be prepared by various conventionally known methods. In particular, it is preferable to form a shell portion (wall film) by using an interfacial polymerization method and microencapsulate the shell portion (wall film) from the viewpoint of homogenizing the shell portion (wall film) and adjusting the thickness of the wall film.

The hardening agent-containing microcapsules obtained by the above interfacial polymerization method can be obtained, for example, as follows.
That is, a polyhydric isocyanate is dissolved therein using a liquid curing accelerator as a core component. The solution obtained in this way is oily, and this is dispersed in the water phase as an oil phase in the form of oil droplets to produce an O / W type (oil phase / water phase type) emulsion. At this time, the average particle size of each dispersed oil droplet is 0.05 to 50 μm, preferably 0.05 to 10 μm.
It is preferred to be about m from the viewpoint of the stability of the emulsion during polymerization.

On the other hand, when a solid curing accelerator is dissolved in an organic solvent to form a core component, an S / O / W (solid phase / oil phase / aqueous phase) type emulsion is obtained. Also, this emulsion type is when the curing accelerator is lipophilic,
When the curing accelerator has hydrophilicity, it is difficult to form the emulsion type, but in this case, the solubility is adjusted so that an O / O (oil phase / oil phase) emulsion type or S / O Interfacial polymerization may be performed as a / O (solid phase / oil phase / oil phase) emulsion type.

Then, polyhydric amines or polyhydric alcohols are added to the aqueous phase of the emulsion to cause interfacial polymerization with polyvalent isocyanates in the oil phase to carry out a polyaddition reaction. A hardening accelerator-containing microcapsule containing a polymer as a shell portion (wall film) is obtained.

The hardening accelerator-containing microcapsules (component (C)) thus obtained are in the form of a core / shell structure, and have a shell containing a hardening accelerator as a core component. The hardening accelerator-containing microcapsules can be isolated by a conventionally known means, for example, a method of drying after centrifugation or a method of spray drying. Further, for example, it can be dissolved and mixed in the thermosetting resin or the curing agent. On this occasion,
If necessary, the organic solvent in the microcapsules can be removed by using a means such as drying under reduced pressure.

The curing accelerator-containing microcapsules (C
As described later, the average particle size of the component is set in the range of 0.05 to 10 μm in consideration of the stability of the microcapsules themselves, the shearing force applied during the production of the epoxy resin composition, uniform dispersibility, and the like. And more preferably 0.1
４4 μm. Further, it is preferable that the maximum particle size of the hardening agent-containing microcapsules (component C) is set to 20 μm or less. That is, by setting the average particle size of the curing accelerator-containing microcapsules (component C) in the above range, it is possible to suppress microcapsule breakage due to shearing force during production of the thermosetting resin composition. In addition, the maximum particle size together with the average particle size is 2
By setting the thickness to 0 μm or less, uniform dispersion in the thermosetting resin can be achieved. In the present invention,
The shape of the curing accelerator-containing microcapsules (component C) is preferably spherical, but may be elliptical. If the microcapsules are not perfectly spherical and the particle diameter is not uniformly determined, such as elliptical or flat, the simple average value of the longest diameter and the shortest diameter is defined as the average particle diameter.

The curing accelerator-containing microcapsules (C
In the component), the amount of the included curing accelerator is preferably set to 5 to 70% by weight, particularly preferably 10 to 50% by weight, based on the total amount of the microcapsules. That is, when the encapsulation amount of the curing accelerator is less than 5% by weight, the curing reaction time is too long, and the reactivity becomes poor. Conversely, when the encapsulation amount of the curing accelerator exceeds 70% by weight, the shell portion (wall film) is formed. ) Is too thin, and there is a possibility that the encapsulated curing accelerator (core component) may have poor isolation and mechanical strength.

The ratio of the shell part (wall film) thickness to the particle size of the hardening accelerator-containing microcapsules (component C) is preferably set to 3 to 25%, particularly preferably 5 to 25%. Is done. That is, the above ratio is 3
%, A sufficient mechanical strength cannot be obtained with respect to the shearing force applied in the kneading step in the production of the thermosetting resin composition,
On the other hand, if it exceeds 25%, the release of the included curing accelerator tends to be insufficient.

The amount of the hardening accelerator-containing microcapsules (component C) is preferably set to 1 to 30 parts with respect to 100 parts by weight (hereinafter abbreviated as "parts") of the epoxy resin. Particularly preferably, the ratio is 5 to 25 parts. That is, if the amount of the curing accelerator-containing microcapsules (component (C)) is too small, such as less than 1 part, the curing speed is too slow to cause a decrease in strength.
If the amount exceeds the part, the curing speed tends to be too high and the fluidity tends to be impaired.

In the above epoxy resin composition, conventionally used various inorganic fillers such as fused silica powder and crystalline silica powder, calcium carbonate, titanium white and the like are used together with the components A to C. . Among them, spherical silica powder, crushed silica powder is preferably used,
Particularly, from the viewpoint of fluidity, it is preferable to use a spherical fused silica powder. And it is preferable to use a thing with a maximum particle diameter of 100 micrometers or less as said inorganic filler. Particularly preferably, the maximum particle size is 50 μm or less. In addition, it is preferable to use those having an average particle diameter of 1 to 20 μm, particularly preferably 2 to 10 μm, together with the maximum particle diameter described above.

It is preferable that the content of the inorganic filler is set within a range of 93% by weight or less based on the whole epoxy resin composition. More preferably 20 to 90% by weight,
Particularly preferably, it is 55 to 85% by weight. That is, when the content of the inorganic filler is less than 20% by weight, the characteristics of the cured resin for encapsulation, particularly the coefficient of linear expansion, become large. There is a possibility that defects such as cracks may occur in objects and semiconductor elements. On the other hand, if it exceeds 93% by weight, the melt viscosity of the encapsulating resin increases, so that the filling property tends to deteriorate.

Further, in addition to the above components A to C and the inorganic filler, the epoxy resin composition may further comprise, if necessary, a silicone compound (eg, side chain ethylene glycol type dimethyl siloxane), acrylonitrile butadiene rubber, or the like. Low stress agents, flame retardants, waxes such as polyethylene and carnauba, coupling agents such as silane coupling agents (such as γ-glycidoxypropyltrimethoxysilane), and ion traps such as bismuth hydroxide and hydrotalcite compounds Agents and the like may be appropriately blended.

Examples of the flame retardant include a brominated epoxy resin, and a flame retardant auxiliary such as diantimony trioxide is used.

The epoxy resin composition used in the present invention is obtained, for example, as follows. First, an epoxy resin (A component), a curing agent (B component) and other additives are blended and pre-kneaded using a mixin chlor, a twin screw extruder, a kneader or the like. On the other hand, a hardening accelerator-containing microcapsule is prepared according to the above-mentioned manufacturing method. Then, the hardening accelerator-containing microcapsules and the remaining components are added to the one obtained by the preliminary kneading, and the mixture is uniformly mixed at a temperature lower than the microcapsule breaking temperature. Thus, the epoxy resin composition is obtained.

In the epoxy resin composition obtained as described above, the curing accelerator-containing microcapsules (component (C)) are usually contained at least in the entire charged amount (blending amount) of the curing accelerator-containing microcapsules. 0.2% by weight remains.

Next, the sheet for sealing a semiconductor element of the present invention can be produced, for example, as follows.
That is, the epoxy resin composition is disposed on one side of the copper foil, and a resin composition layer is formed by rolling, or hot melt coating is performed on one side of the copper foil to form a resin composition layer. In addition, a resin composition layer is formed on a predetermined portion of the copper foil surface according to a screen printing technique. Further, an epoxy resin composition is dropped on the copper foil surface by using a dispenser and is spread to a predetermined thickness to form a resin composition layer. In this way, a semiconductor element sealing sheet can be manufactured. The resin composition layer can be formed using the dispenser, but is preferably formed by screen printing in consideration of the quantitative accuracy.

Then, a sheet having only the resin composition layer is prepared in advance, cut into a predetermined shape, and the cut is attached to a copper foil to prepare a sheet for sealing a semiconductor element. be able to. As a method for producing a sheet-like material having only the resin composition layer, for example, it can be produced by forming a resin composition layer having a predetermined thickness by rolling on release paper (separator). Also,
It can also be produced by forming a resin composition layer having a predetermined thickness by hot-melt coating on release paper (separator).

Further, the semiconductor element encapsulating sheet obtained as described above is applied to the shape of the semiconductor device and the like.
It may be punched or cut into a predetermined shape. As the punching method, a method using a Thomson blade,
Although a method using a mold and the like can be mentioned, a method using a mold is preferable in consideration of a problem such as “burr” generated at the time of punching.

The thickness of the copper foil in the semiconductor element encapsulating sheet is preferably set in the range of 30 to 200 μm, particularly preferably 50 to 200 μm. The thickness of the resin composition layer is preferably set in the range of 50 to 300 μm, particularly preferably 80 to 2 μm.
00 μm. Therefore, the total thickness of the entire semiconductor element sealing sheet is set in the range of 80 to 500 μm, and preferably 100 to 400 μm.

Further, the size (area) of the copper foil and the resin composition layer of the semiconductor element encapsulating sheet is appropriately set according to the size of the semiconductor element to be sealed, the wiring portion to be sealed, and the like. Usually, copper foil is 1 × 1 to 50 × 50
It is preferably set in the range of mm, particularly preferably 2 × 2 to 30 × 30 mm. In the semiconductor element sealing sheet, the relationship between the area of the copper foil and the area of the resin composition layer is such that the area of the resin composition layer 2 is smaller than the area of the copper foil 1 as shown in FIG. The setting is not limited, and the area of the resin composition layer 2 and the area of the copper foil 1 may be set to be equal.

Next, an example of a method of manufacturing a semiconductor device using the above-mentioned semiconductor element encapsulating sheet will be specifically described in order with reference to the drawings.

First, as shown in FIG.
The semiconductor element 22 provided with the lead 23 on which the insulating layer 24 has been formed is arranged. On the other hand, in a state where the semiconductor element 22 and the resin composition layer 2 face each other above the semiconductor element 22,
The semiconductor element sealing sheet 26 is mounted on the suction head 21 and arranged.

Next, as shown in FIG. 3, the semiconductor element encapsulating sheet 26 mounted on the suction head 21 is pressed against the semiconductor element 22 disposed on the mold 20 and is embedded in the suction head 21. The heater 26 heats the semiconductor element encapsulating sheet 26 to heat and melt the resin composition layer 2. Then, the mold 20 and the suction head 21 are held in a state where the distance between them is a predetermined distance. Next, the resin composition layer 2 is cured by heating and released from the mold 20.
In this way, as shown in FIG. 4, it is possible to obtain a semiconductor device in which one side of the semiconductor element 22 is resin-sealed by the sealing resin layer 27 and the copper foil 1 is further provided on the surface of the sealing resin layer 27. it can.

In the above-described manufacturing process, the thickness of the semiconductor device is such that a distance for holding the mold 20 and the suction head 21 at a predetermined interval can be obtained. The holding time may be sufficient until the resin sealing layer is gelled. Usually, it is about 1 to 2 minutes at 175 ° C and about 30 to 60 seconds at 200 ° C. Further, it is preferable to set the pressure condition at this time to 0.005 to 1 kg / cm ² .

In the above manufacturing method, it is possible to appropriately set the predetermined interval to be held, and it is possible to obtain a semiconductor device having a small thickness, for example, a thickness of 0.3 to 0.7 mm.

In the method of manufacturing a semiconductor device described above, the heating temperature for heating and curing the resin composition layer is 70 to 300 ° C. in consideration of the deterioration of the semiconductor element 22 and the like.
Is preferably set in the range of, particularly preferably 12
0-200 ° C. As a heating method, a heater built in each suction head 21 is used in the above manufacturing method, but the heating method is not limited to this, and an infrared reflow oven, a dryer, a hot air machine, a hot plate, or the like can also be used. .

The sealing resin layer 27 formed by sealing using the semiconductor element sealing sheet, that is,
As the characteristics of the resin composition layer, the melt viscosity at each use temperature is 1 to 200 poise, the gel time is 1 to 15 minutes at 150 ° C., and the cured product has a linear expansion coefficient of 8 × 10 ⁻⁶ to 70 ×. It is preferably 10 ^-6 / ° C.
More preferably, the melt viscosity is 1 to 100 poise, the gel time is 1 to 12 minutes at 150 ° C., and the linear expansion coefficient is 10 × 10 ⁻⁶ to 30 × 10 ⁻⁶ / ° C. That is, the filling property is improved by setting the melt viscosity within the above range. Further, by setting the gel time within the above range, the molding workability, particularly the curing time, can be shortened. Further, by setting the linear expansion coefficient within the above range, it becomes possible to prevent defects due to stress such as cracks in the cured resin or the semiconductor element. The melt viscosity was measured with an ICI cone plate viscometer, and the gel time was measured on a hot plate. The coefficient of linear expansion was measured by thermomechanical analysis (TMA).

The semiconductor device manufactured using the semiconductor element encapsulating sheet of the present invention is not limited to the embodiment shown in FIG. 4, and for example, as another example,
A semiconductor device having the form shown in FIG. That is,
As shown in FIG. 5, only the semiconductor element 22 mounting surface of the semiconductor element 22
Resin sealing, and further, a copper foil 3
1 is a single-sided sealing type semiconductor device. In FIG. 5, reference numeral 32 denotes a lead. Examples of the substrate 29 in such a type of semiconductor device include a flexible printed circuit board.

FIG. 6 shows another example of a semiconductor device manufactured using the semiconductor element sealing sheet of the present invention. That is, in this semiconductor device, only one surface of the semiconductor element 22 provided in the substrate 33 is resin-sealed with the sealing resin layer 34, and the copper foil 31 is further provided on the surface of the sealing resin layer 34. This is a single-sided sealing type semiconductor device. In FIG. 6, reference numeral 35 denotes a lead.

Since the semiconductor device thus obtained is manufactured using the above-mentioned semiconductor element sealing sheet, it is possible to easily manufacture a thin type which has been difficult in the past. For example, a thin semiconductor device having a thickness of about 0.1 to 0.3 mm can be obtained. Such a thin semiconductor device is used in various electronic devices in recent years, and is most suitable for use in IC cards and the like.

Next, examples will be described together with comparative examples.

First, prior to the examples, the following components were prepared.

[Epoxy resin a] Hydroquinone type epoxy resin [Epoxy resin represented by the formula (2), epoxy equivalent: 173 g / eq, melting point: 138 ° C.]

[Epoxy resin b] Biphenyl type epoxy
Resin [Epoxy resin represented by the formula (1) (R₁~ R
_FourAre all methyl groups) epoxy equivalent: 195 g / eq, melting
(Point: 108 ° C)

[Phenol resin] Novolak phenol resin (hydroxyl equivalent: 104 g / eq, softening point: 64 ° C.)

[Flame retardant] Brominated epoxy resin (bromine content: 48% by weight, epoxy equivalent: 460 g / eq)

[Flame retardant aid] diantimony trioxide

[Hydrotalcite compound] DHT-4
A, manufactured by Kyowa Chemical Company

[Inorganic filler] Spherical fused silica powder (average particle size 10 μm, maximum particle size 50 μm or less)

[Hardening Accelerator-Containing Microcapsules c1]
It was produced by the above-mentioned interfacial polymerization method. More specifically, an oil phase was prepared by uniformly dissolving 10 parts of an adduct of 3 mol of xylylene diisocyanate and 1 mol of trimethylolpropane in 4 parts of triphenylphosphine as a curing agent. Further, an aqueous phase composed of 95 parts of distilled water and 5 parts of polyvinyl alcohol was separately prepared, and the oil phase prepared above was added thereto, and a homomixer (8000 rpm) was added.
m) to emulsify to an emulsion state,
The polymerization reactor was equipped with a stirrer and a dropping funnel.

On the other hand, 13 parts of an aqueous solution containing 3 parts of triethylenetetramine was prepared, placed in a dropping funnel provided in the polymerization reactor, dropped into the emulsion in the reactor, and polymerized at 70 ° C. for 3 hours. Then, microcapsules c1 were produced. A polyurea shell containing triphenylphosphine in this manner [shell thickness ratio to particle size 20%: a repeating unit represented by the above formula (4) in which R ₁ is hydrogen and R ₂ is hydrogen is a main component. The microcapsules c1 having the above structure were produced (the average particle diameter was 1 μm and the maximum particle diameter was 8 μm).

[Microcapsules c2 containing curing accelerators]
It was produced by the above-mentioned interfacial polymerization method. The preparation method was the same as that described above, but the homomixer used for emulsification and preparation of the emulsion was performed at 3000 rpm. A polyurea shell containing triphenylphosphine in this manner [shell thickness ratio to particle size 20%: a repeating unit represented by the above formula (4) in which R ₁ is hydrogen and R ₂ is hydrogen is a main component. The microcapsules c2 having the above structure were produced (the average particle size was 15 μm and the maximum particle size was 30 μm)

[0081]

Examples 1 to 4 (1) Preliminary kneading step Each of the above components was blended at the ratio shown in Table 1 below, and preliminarily kneaded using a twin screw extruder.

(2) Pot Kneading Step Next, each component is blended with the pre-kneaded product obtained in the above-mentioned pre-kneading step so as to have the ratio shown in Table 1 below, and the pot is kneaded using a pot. Thus, an epoxy resin composition was prepared.

[0083]

[Table 1]

(3) Production of Semiconductor Element Encapsulating Sheet A semiconductor element encapsulating sheet was produced using the epoxy resin composition as follows. That is, the above epoxy resin composition was screen printed to a thickness of 50 μm.
A resin composition layer having a thickness of 150 μm was formed on the surface of the copper foil (thermal conductivity 0.94 cal / cm · sec · ° C.). Thus, a semiconductor element sealing sheet was produced.

[0085]

Comparative Example 1 Instead of the copper foil of Example 1, the thickness was 50 μm.
42 nickel-iron alloy foil (thermal conductivity 0.032cal / cm
· Sec · ° C). Otherwise in the same manner as in Example 1, a sheet for sealing a semiconductor element was produced.

[0086]

COMPARATIVE EXAMPLE 2 Using the epoxy resin composition of Example 1, a sheet for encapsulating a semiconductor element was produced which was composed of the epoxy resin composition alone (no copper foil). That is, a separator was used in place of the copper foil, and an epoxy resin composition layer was formed on the separator by screen printing.

The obtained sheets for encapsulating a semiconductor element were subjected to an evaluation test described later.

Using the semiconductor element sealing sheet thus obtained, a semiconductor device was manufactured according to the above-described semiconductor device manufacturing method. That is, as shown in FIG.
The semiconductor element 22 (size: 14 × 14 mm) provided with the lead 23 on which the insulating layer 24 has been formed was disposed in the area 0. On the other hand, a semiconductor element sealing sheet 26 was mounted on the suction head 21 in a state where the semiconductor element 22 and the resin composition layer 2 faced each other above the semiconductor element 22.

Next, as shown in FIG. 3, the semiconductor element encapsulating sheet 26 mounted on the suction head 21 is pressed against the semiconductor element 22 disposed on the mold 20 and is embedded in the suction head 21. The semiconductor element encapsulating sheet 26 was heated by the heater to melt the resin composition layer 2 (pressing and heating conditions: 0.1 kg / cm ² , 175)
° C). Then, after maintaining the state in which the distance between the mold 20 and the suction head 21 is 0.5 mm, the resin composition layer 2 is cured by heating (curing conditions: 175 ° C. × 2 minutes). Demolded from. In this manner, as shown in FIG. 4, one side of the semiconductor element 22 is resin-sealed by the sealing resin layer 27, and the copper foil 1 (the comparative example 1 is a 42 nickel-iron alloy foil). ) Was prepared (0.6 mm thick). In Comparative Example 2, only the resin sealing layer 27 was formed without the copper foil 1, and the thickness of the semiconductor device was 0.6 mm.

The obtained semiconductor device having a thickness of 0.6 mm was subjected to a pressure cooker test (PCT test (conditions: left at 121 ° C. × 2 atm × 100% RH for 200 hours)) and then checked for energization. Then, the rate of occurrence of defects (defect occurrence rate) was calculated. Along with the defect occurrence rate, those in which a defect occurred were indicated by x, and those in which no defect occurred were indicated by ○.

The heat dissipation of the obtained semiconductor device was measured and evaluated as follows. That is, SEMI
Performed according to G38-87. The lower the measured value, the better the heat dissipation.

The results are shown in Table 2 below.

[0093]

[Table 2]

From the results shown in Table 2 above, it can be seen that the product of the example obtained a good thin semiconductor device having high heat dissipation properties. On the other hand, it can be seen that Comparative Examples 1 and 2 are inferior to the Examples in heat dissipation.

[0095]

As described above, according to the present invention, a resin composition layer composed of an epoxy resin composition containing microcapsules (component (C)) containing a special curing accelerator is formed on a substrate surface composed of a copper foil. This is a formed semiconductor element sealing sheet.
As described above, the special curing accelerator-containing microcapsules (C) are contained in the resin composition layer of the semiconductor element encapsulating sheet.
Component), the semiconductor encapsulating sheet can be easily manufactured without causing a curing reaction to proceed even by heating or the like during the production of the sheet. Further, the above-mentioned semiconductor element sealing sheet includes a
Since a resin composition layer having a necessary minimum amount of resin can be formed so as not to generate an excessive resin component, generation of excess resin can be suppressed at the time of manufacturing a semiconductor device.

After the semiconductor element encapsulating sheet is arranged in a state where the resin composition layer of the semiconductor element encapsulating sheet and the semiconductor element face each other, the semiconductor element and the semiconductor element encapsulating sheet are removed. The semiconductor device can be manufactured by bonding and heat-melting the resin composition layer of the semiconductor element sealing sheet and then curing the molten resin composition layer. Therefore, a semiconductor device can be easily manufactured without going through complicated steps. Further, at this time, the resin composition in a molten state can be held without causing the curing reaction to proceed during the heating and melting, and the sealing resin layer can be set to a desired thickness. It is easy to manufacture.

In addition, since a copper foil is provided on the resin sealing surface of the obtained semiconductor device, heat generated in the semiconductor device can be efficiently released to the outside. Therefore, the reliability of the semiconductor device can be maintained without lowering the reliability. Therefore, a semiconductor device obtained using such a semiconductor element encapsulating sheet is effective as an application in which the thickness tends to be thin in recent years, and is most suitable, for example, for manufacturing a semiconductor device incorporated in an IC card or the like.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of a semiconductor element sealing sheet of the present invention.

FIG. 2 is an explanatory view schematically showing an example of a manufacturing process of a semiconductor device using the semiconductor element sealing sheet of the present invention.

FIG. 3 is an explanatory view schematically showing an example of a manufacturing process of a semiconductor device using the semiconductor element sealing sheet of the present invention.

FIG. 4 is a cross-sectional view illustrating an example of a semiconductor device obtained through a process of manufacturing the semiconductor device.

FIG. 5 is a cross-sectional view showing another example of a semiconductor device obtained by using the semiconductor element sealing sheet of the present invention.

FIG. 6 is a cross-sectional view showing still another example of a semiconductor device obtained by using the semiconductor element sealing sheet of the present invention.

FIG. 7 is a sectional view showing a semiconductor device obtained by a conventional transfer molding method.

FIG. 8 is a sectional view showing a semiconductor device obtained by a conventional potting method.

FIG. 9 is a sectional view showing a semiconductor device obtained by a conventional potting method.

FIG. 10 is a sectional view showing a semiconductor device obtained by a conventional potting method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copper foil 2 Resin composition layer 20 Die 21 Suction head 22 Semiconductor element 26 Semiconductor element sealing sheet 27 Sealing resin layer

Continued on the front page F-term (reference) 4J036 AC01 AC05 AD07 AD08 DA05 DB21 DC25 DC26 DC36 DC39 DC41 DC46 DD07 FB07 HA07 JA07 4M109 AA01 BA05 CA22 EA02 EB02 EB03 EB04 EB06 EB07 EB08 EB09 EB12 EB18 EB19 GA03 BA03 DE04

Claims (4)

[Claims] 1. The following (A) is formed on a substrate surface made of copper foil.
A sheet for encapsulating a semiconductor element, wherein a resin composition layer comprising an epoxy resin composition containing components (C) to (C) is formed. (A) Epoxy resin. (B) a curing agent. (C) A hardening accelerator-containing microcapsule having a core / shell structure in which a core made of a hardening accelerator is covered with a shell made of a thermoplastic resin. 2. The semiconductor element sealing sheet according to claim 1, wherein said copper foil has a thickness of 30 to 200 μm. 3. A step of disposing the semiconductor element encapsulating sheet on a semiconductor element in a state where the resin composition layer of the semiconductor element encapsulating sheet according to claim 1 and the semiconductor element face each other; A step of adhering the semiconductor element and the semiconductor element encapsulating sheet, a step of heating and melting the resin composition layer of the semiconductor element encapsulating sheet, and a step of curing the molten resin composition layer to form a semiconductor element And a step of resin-sealing the semiconductor device. 4. A semiconductor device obtained by the method for manufacturing a semiconductor device according to claim 3, wherein one side of the semiconductor element is a cured product made of an epoxy resin composition containing the components (A) to (C). And a copper foil disposed on the surface of the cured body.