JP4137827B2 - Conductive adhesive film and semiconductor device using the same - Google Patents

Description

  The present invention relates to a conductive adhesive film and a semiconductor device using the same.

  The method of bonding a semiconductor element to a metal lead frame or the like in the manufacture of a semiconductor device (so-called die bonding method) has been changed from a conventional gold-silicone eutectic method to a solder or resin paste method. At present, a method using a conductive resin paste is mainly used.

However, in the method using a conductive resin paste, there is a case where a decrease in conductivity due to generation of voids, a non-uniform paste thickness, and the like occur.
Further, in a semiconductor device using a high density mounting method such as BGA (Ball Grid Array) and CSP (Chip Scale Package) developed in recent years, there is a problem that the resin paste protrudes after bonding.

As a technique for solving these problems, a film-like adhesive using polyimide has been proposed (for example, see Patent Document 1).
Since this film-like adhesive contains a large amount of silver particles, its flexibility is insufficient and workability is inferior. In addition, since a film-like adhesive using polyimide needs to be bonded at a high temperature, it may cause thermal damage to a densified semiconductor element, a lead frame, or the like.

Japanese Patent Application Laid-Open No. 6-145639

  An object of the present invention is to provide a conductive adhesive film having excellent conductivity and good workability, and a semiconductor device using the same.

Such an object is achieved by the present invention described in (1) to ( 6 ).
(1) A conductive adhesive film comprising a thermoplastic resin and a resin composition containing silver powder as conductive particles, wherein the thermoplastic resin is acrylic acid and / or methacrylic acid ester.
It is an acrylic acid copolymer having tellur as an essential copolymerization component, the glass transition temperature of the thermoplastic resin is -10 to 50 ° C, and the content of the silver powder is 60 to 90% by weight of the whole resin composition Furthermore, the elongation at break after the curing treatment of the conductive adhesive film is 2% or more.
(2) The conductive adhesive film according to (1), wherein the resin composition further contains a curable resin.
( 3 ) The conductive adhesive film according to (2) , wherein the acrylic acid copolymer includes a compound having a nitrile group.
( 4 ) The conductive adhesive film according to (2) or (3) , wherein the acrylic acid copolymer includes a compound having an epoxy group.
( 5 ) The conductive adhesive film according to any one of (1) to ( 4 ), wherein a volume resistance value of the conductive adhesive film is 10 ⁻³ Ω · cm or less.
( 6 ) A semiconductor device, wherein a semiconductor element and a support member are bonded via the conductive adhesive film according to any one of (1) to ( 5 ).

According to the present invention, it is possible to obtain a conductive adhesive film excellent in conductivity and workability and a semiconductor device using the same.
Moreover, when using a specific acrylic acid copolymer, it is excellent in adhesiveness especially at high temperature, and can improve connection reliability.

Hereinafter, the conductive adhesive film and the semiconductor device of the present invention will be described.
The conductive adhesive film of the present invention is a conductive adhesive film composed of a resin composition containing an acrylic resin and conductive particles, and the elongation at break after the curing treatment of the conductive adhesive film is 2 % Or more.
The semiconductor device of the present invention is characterized in that the semiconductor element and the support member are joined via the conductive adhesive film described above.

First, the conductive adhesive film will be described.
The thermoplastic resin imparts flexibility to the conductive adhesive film. The conductive particles impart conductivity. In addition, when the breaking elongation after the curing treatment of the conductive adhesive film is 2% or more, the conductive adhesive film can be used as a dicing film, and the dicing property can be particularly improved. It is.
Here, “after the curing treatment” means that the conductive adhesive film having a thickness of 10 to 100 μm is treated at 180 ° C. for 1 hour.

Hereinafter, each component will be specifically described.
Examples of the thermoplastic resin include elastomers such as acrylonitrile-butadiene copolymer (NBR), acrylonitrile-butadiene rubber-styrene resin (ABS), polybutadiene, styrene-butadiene-ethylene resin (SEBS), polyamide, and polyamideimide. Examples include polyamide resins, polyimide resins such as polyimide, polyvinyl butyral, polyester, polyurethane, phenoxy resin, and acrylic resins. Among these, acrylic resins (particularly copolymers having acrylic acid and / or methacrylic acid ester as essential copolymerization components) are preferable. Thereby, adhesiveness with adherends, such as a semiconductor element, can be improved especially. Furthermore, flexibility and relaxation effects during thermal stress can be improved.

  The thermoplastic resin may have a functional group capable of reacting with a thermosetting resin described later. Specific examples of the functional group include an amino group, a carboxyl group, an epoxy group, a hydroxyl group, a methylol group, an isocyanate group, a vinyl group, and a silanol group. These functional groups are preferable because the bond with the thermosetting resin becomes stronger and the heat resistance is improved.

  The acrylic resin means acrylic acid and its derivatives. Specifically, acrylic acid such as acrylic acid, methacrylic acid, methyl acrylate and ethyl acrylate, methacrylic acid such as methyl methacrylate and ethyl methacrylate Examples thereof include polymers such as esters, acrylonitrile and acrylamide, and copolymers with other monomers.

  The acrylic resin (especially acrylic acid copolymer) may also have a functional group capable of reacting with a thermosetting resin described later. Specific examples include an amino group, a carboxyl group, an epoxy group, a hydroxyl group, a methylol group, an isocyanate group, a vinyl group, and a silanol group. In this case, it is more preferable to use a copolymer having a nitrile group as a functional group. Thereby, the adhesiveness to adherends, such as a semiconductor element, can be improved more.

Specific examples of the compound having a functional group include glycidyl methacrylate having a glycidyl ether group, hydroxy methacrylate having a hydroxyl group, carboxy methacrylate having a carboxyl group, and acrylonitrile having a nitrile group.
Among these, an acrylic acid copolymer containing a compound having a nitrile group or an epoxy group is particularly preferable. Thereby, the adhesiveness to a to-be-adhered body can be improved especially.
The compound having such a functional group may constitute one of the copolymer components of the acrylic resin, or may be simply mixed.

  The content of the compound having a functional group is not particularly limited, but is preferably 0.5 to 40% by weight, particularly preferably 5 to 30% by weight, based on the entire acrylic resin. When the content is less than the lower limit, the effect of improving the adhesion may be reduced, and when the content exceeds the upper limit, the adhesive force is too strong and the effect of improving the workability may be reduced.

  Although the glass transition temperature of the said thermoplastic resin (especially acrylic resin) is not specifically limited, -10-50 degreeC is preferable and 0-40 degreeC is especially preferable. When the glass transition temperature is less than the lower limit, the adhesive strength is increased and the effect of improving workability may be reduced. When the glass transition temperature exceeds the upper limit, the conductive adhesive film may be too brittle.

  Although content of the said thermoplastic resin (especially acrylic resin) is not specifically limited, 5-30 weight% of the whole said resin composition is preferable, and 10-20 weight% is especially preferable. If the content is less than the lower limit, the effect of improving the flexibility of the conductive adhesive film may be reduced, and if the content exceeds the upper limit, the workability of the conductive adhesive film may be reduced.

The weight average molecular weight of the thermoplastic resin (especially acrylic resin) is not particularly limited, but is preferably 100,000 or more, particularly preferably from 1 to 1,000,000. If the weight average molecular weight is less than the lower limit, the strength of the conductive adhesive film may be reduced, and if the upper limit is exceeded, the effect of improving the compatibility with the curable resin may be reduced.

Examples of the conductive particles include gold, silver, copper, iron, nickel, SUS, and carbon black. Among these, silver (especially silver powder) and copper are preferable. Thereby, it is excellent in electroconductivity.
The shape of the conductive particles is not particularly limited, and examples thereof include a crushed shape, a spherical shape, and a scale shape. Of these, scaly is preferable. Thereby, workability | operativity can be improved.

  Although the average particle diameter of the said electroconductive particle is not specifically limited, 0.5-20 micrometers is preferable and 1-10 micrometers is especially preferable. When the average particle diameter is within the above range, the appearance of the conductive adhesive film is particularly excellent.

Although content of the said electroconductive particle is not specifically limited, 60 to 90 weight% of the whole said resin composition is preferable, and 70 to 80 weight% is especially preferable. When the content is within the above range, the conductivity of the adhesive film for a semiconductor is particularly excellent.
Further, when silver (silver powder) is used as the conductive particles, the silver powder is not particularly limited, but preferably includes flaky silver powder, and it is particularly preferable to use flaky silver powder and spherical silver powder in combination, It is preferable to use most flaky silver powder, spherical silver powder and customized silver powder in combination. Thereby, workability | operativity can be improved in the state which maintained the outstanding electroconductivity.

  The above-mentioned admired silver powder is obtained by an admixed method, and is obtained by spray cooling after silver is melted. The said managed silver powder does not have a space | gap between particle | grains, does not have a heat conductive fall, and has the characteristics to provide heat dissipation.

The average particle diameter of the flaky silver powder is not particularly limited, but is preferably 1 to 15 μm, and particularly preferably 3 to 10 μm. When the average particle diameter of the flaky silver powder is within the above range, particularly the viscosity of the conductive adhesive film can be reduced and the silver powder can be highly filled.
Furthermore, the flaky silver powder preferably has a maximum particle size of 30 μm or less, particularly 10 to 25 μm, in addition to the range of the average particle size. Thereby, in addition to the effect of decreasing the viscosity, the appearance of the conductive adhesive film can also be improved.

The average particle diameter of the spherical silver powder is not particularly limited, but is preferably 0.3 to 3.0 μm, particularly preferably 0.5 to 2.5 μm. When the average particle diameter of the spherical silver powder is within the above range, particularly the adhesiveness of the conductive adhesive film can be improved.
Further, the spherical silver powder preferably has a maximum particle size of 30 μm or less, particularly 10 to 25 μm, in addition to the range of the average particle size. Thereby, in addition to the effect which improves the said adhesiveness, the external appearance of a conductive adhesive film can also be improved.

The average particle size of the above-mentioned admixed silver powder is preferably 3 to 10 μm, particularly preferably 5 to 8 μm. When the average particle diameter is within the above range, particularly the adhesiveness of the conductive adhesive film can be improved. Furthermore, the Adomaizudo silver powder, in addition to the range of the average particle diameter is preferably tap density of 4.5 g / cm ³ or more, and particularly 5.0~6.0g / cm ³ preferred. Thereby, the filling property of silver powder can be improved. The said tap density can be measured by the method according to 20.2 tap method of JISK5101-1991, for example.

Although content of the said flaky silver powder is not specifically limited, 20 to 80 weight% of the said resin composition is preferable, and 30 to 70 weight% is especially preferable. When the content is within the above range, the balance of conductivity, adhesiveness and workability is particularly excellent.
Moreover, the content of the spherical silver powder is not particularly limited, but is preferably 5 to 20% by weight, and particularly preferably 8 to 18% by weight of the resin composition. If the content is within the above range, the thixotropy can be further improved.
Further, the content of the above-mentioned admired silver powder is not particularly limited, but is preferably 15 to 50% by weight, and particularly preferably 20 to 45% by weight of the resin composition. When the content is within the above range, the conductivity can be further improved.

It is preferable that the resin composition further contains a curable resin. Thereby, wettability can be improved at the time of thermocompression bonding. In addition, as curable resin, what has a function as a hardening | curing agent which is mentioned later may be included. Furthermore, by the heating after thermocompression bonding, the curing reaction proceeds to form a three-dimensional network, and the adhesion between the semiconductor element and a support member such as a metal lead frame can be improved.
Examples of the curable resin include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, phenol resin such as resole phenol resin, bisphenol such as resorcinol resin, bisphenol A epoxy resin, and bisphenol F epoxy resin. Type epoxy resin, novolac epoxy resin, novolak type epoxy resin such as cresol novolak epoxy resin, biphenyl type epoxy resin, stilbene type epoxy resin, triphenolmethane type epoxy resin, alkyl-modified triphenolmethane type epoxy resin, epoxy resin containing triazine nucleus , Epoxy resins such as dicyclopentadiene-modified phenolic epoxy resins, triazine rings such as urea (urea) resins and melamine resins Resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl phthalate resin, silicone resin, resin having benzoxazine ring, bisphenol A dicyanate resin, bisphenol F dicyanate resin, bis (4-cyanate phenyl) ether resin, bisphenol Examples thereof include thermosetting resins such as bisphenol type cyanate resins such as E dicyanate resin and cyanate ester resins such as novolak type cyanate resin, and these may be used alone or in combination. Among these, an epoxy resin is particularly preferable. Thereby, heat resistance and adhesiveness can be improved more.

Although content of the said thermosetting resin is not specifically limited, 1 to 10 weight% of the whole said resin composition is preferable, and 3 to 8 weight% is especially preferable. If the content is less than the lower limit, the effect of improving the heat resistance may be reduced, and if the content exceeds the upper limit, the storage stability may be reduced.
Here, storability means the property that the varnish of the adhesive film for semiconductor can be stored at room temperature.

  When an epoxy resin is used as the curable resin, the content is not particularly limited, but is preferably 1 to 8% by weight, and particularly preferably 3 to 7% by weight of the entire resin composition. If the content is less than the lower limit, the effect of improving the heat resistance may be reduced, and if the content exceeds the upper limit, the storage stability may be reduced.

When an epoxy resin is used as the curable resin, the weight average molecular weight is not particularly limited, but is preferably 300 to 2,000, particularly preferably 500 to 800. If the weight average molecular weight exceeds the upper limit, the compatibility with the acrylic resin may be reduced, and if it is less than the lower limit, a volatile component may be generated during thermocompression bonding or thermosetting.
The epoxy equivalent of the epoxy resin is not particularly limited, but is preferably 100 to 2,000 g / eq, and particularly preferably 120 to 1,800 g / eq. If the epoxy equivalent is less than the lower limit, the crosslink density may decrease and the heat resistance may decrease, and if the upper limit is exceeded, the conductive adhesive film may become brittle.

Further, the epoxy resin is preferably a combination of a solid epoxy resin at room temperature and a liquid epoxy resin at room temperature. Thereby, the flow property at the time of adhere | attaching a semiconductor element etc. with a conductive adhesive film (wet spreading property of a conductive adhesive film) can be improved.
The combination ratio of the epoxy resin that is solid at room temperature and the liquid epoxy resin is not particularly limited, but the solid epoxy resin / liquid epoxy resin is preferably 9/1 to 5/5 in weight ratio, particularly 8 / 2 to 6/4 is preferable. When the combined proportion is within the above range, the flowability of the conductive adhesive film can be particularly improved.

  In addition to the components listed above, epoxy oligomers can also be used for the thermosetting resin. Examples of the epoxy oligomer include those having at least one epoxy group in the molecule, and preferably have a molecular weight of 1,000 to 50,000, particularly preferably 3,000 to 10,000.

Furthermore, when using the said epoxy resin as curable resin, although it does not specifically limit, It is still more preferable to use together cyanate ester resin. Thereby, the adhesiveness to a to-be-adhered body and heat resistance can be improved more.
Although content of the said cyanate ester resin is not specifically limited, 0.1 to 8 weight% of the whole said resin composition is preferable, and 0.5 to 5 weight% is especially preferable. If the content is less than the lower limit value, the effect of improving the adhesion may be reduced, and if the content exceeds the upper limit value, the cause of outgassing and the effect of improving the heat resistance may be reduced.

Moreover, when using an epoxy resin as said curable resin, although it does not specifically limit, In order to accelerate | stimulate reaction of an epoxy resin, it is preferable to add a hardening accelerator.
Examples of the curing accelerator include dicyandiamide derivatives, imidazoles, and triphenylphosphine. Two or more of these may be used in combination. Of these, imidazoles are preferably used. Specific examples of imidazoles include 1-benzyl-2-methylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 1-benzyl-2-phenylimidazole, 1 -Cyanoethyl-2-methyl-imidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole and the like.

  Although the compounding quantity of the said hardening accelerator is not specifically limited, 0.01 to 5 weight% of the whole said resin composition is preferable, and 0.03 to 2 weight% is especially preferable. When the blending amount is within the above range, the reactivity of the epoxy resin is particularly excellent.

When the curable resin is an epoxy resin, the resin composition may include a curing agent (particularly, an imidazole curing agent).
Examples of the curing agent include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA), diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone. In addition to aromatic polyamines such as (DDS), amine-based curing agents such as polyamine compounds including dicyandiamide (DICY) and organic acid dihydralazide, and fats such as hexahydrophthalic anhydride (HHPA) and methyltetrahydrophthalic anhydride (MTHPA) Acid anhydride curing agents such as aromatic acid anhydrides such as cyclic acid anhydride (liquid acid anhydride), trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenone tetracarboxylic acid (BTDA) , Phenolic tree Phenolic curing agent and the like. Among these, a phenolic curing agent is preferable, and specifically, bis (4-hydroxy-3,5-dimethylphenyl) methane (common name: tetramethylbisphenol F), 4,4′-sulfonyldiphenol, 4,4′- Isopropylidene diphenol (commonly called bisphenol A), bis (4-hydroxyphenyl) methane, bis (2-hydroxyphenyl) methane, (2-hydroxyphenyl) (4-hydroxyphenyl) methane and bis (4-hydroxy) Bisphenols such as three mixtures of phenyl) methane, bis (2-hydroxyphenyl) methane, and (2-hydroxyphenyl) (4-hydroxyphenyl) methane (for example, bisphenol FD manufactured by Honshu Chemical Industry Co., Ltd.) , 1,2-benzenediol, 1,3-benzenediol Dihydroxybenzenes such as 1,4-benzenediol, trihydroxybenzenes such as 1,2,4-benzenetriol, various isomers of dihydroxynaphthalenes such as 1,6-dihydroxynaphthalene, 2,2′-biphenol, Examples of the compound include various isomers of biphenols such as 4,4′-biphenol.

  The content of the curing agent for the epoxy resin is not particularly limited, but is preferably 0.5 to 30% by weight, particularly preferably 3 to 10% by weight, based on the entire resin composition. If the content is less than the lower limit, the effect of improving the heat resistance may be reduced, and if the content exceeds the upper limit, the storage stability may be reduced.

  As the curing agent, a reaction product of an epoxy resin and an amine compound can also be used. This is called a microcapsule type curing agent, and the amine compound added by heating is released from the epoxy resin and acts on the epoxy resin. For example, there is a bisphenol F-type epoxy resin and 2-methylimidazole added with isocyanate.

Additives such as a coupling agent can be used in the resin composition as necessary.
Examples of the coupling agent include silane coupling agents, titanate coupling agents, and aluminum coupling agents. Among these, a silane coupling agent having good adhesion at the interface with the silicon chip is preferable. Specifically, γ-glycidoxypropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, β- (3,4-epoxy (Cyclohexyl) ethyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like.

  The content of the coupling agent is not particularly limited, but is preferably 0.5 to 10 parts by weight, particularly preferably 0.8 to 8 parts by weight, based on 100 parts by weight of the resin component (acrylic resin + curable resin). . When the blending amount is within the above range, the adhesion is particularly excellent.

The conductive adhesive film of the present invention can be obtained, for example, by the following method.
The resin composition is mixed in an organic solvent such as N-methyl-2-pyrrolidone, anisole, methyl ethyl ketone, toluene, and ethyl acetate to form a varnish, which is then flowed to a heat resistant film support substrate such as polyimide. The conductive adhesive film of the present invention can be obtained by coating with a coater, roll coater, comma coater or the like to form a film, followed by thermosetting treatment.

The breaking elongation after (thermal) curing treatment of the conductive adhesive film is 2% or more. More specifically, the breaking elongation of the conductive film is preferably 2.5% or more, particularly preferably 3 to 10%. When the breaking elongation is within the above range, the conductive film can be used as a dicing film, and the dicing property can be particularly improved.
The breaking elongation can be measured, for example, on a conductive film cut to a thickness of 25 μm, a length of 120 mm, and a width of 10 mm using a universal tensile tester at a speed of 5 mm per minute.

The volume resistance value of the conductive adhesive film is not particularly limited, but is preferably 10 ⁻³ Ω · cm or less, and particularly preferably 10 ⁻⁴ to 10 ⁻⁵ Ω · cm. When the volume resistance value is within the above range, the heat dissipation property of the conductive adhesive film is improved, so that an adhesive film suitable for the latest semiconductor device corresponding to downsizing and high-density mounting can be obtained.

Next, the semiconductor device of the present invention will be described based on a preferred embodiment.
FIG. 1 is a cross-sectional view schematically showing an example of a semiconductor device of the present invention.
The semiconductor device 1 includes a semiconductor element 2, a conductive adhesive film 3, and a support member 4.
The semiconductor element 2 is bonded to the support member 4 through the conductive adhesive film 2 as described above.

  Examples of the support member 4 include a metallic lead frame, a substrate obtained by impregnating glass fiber with an epoxy resin, a polyimide resin substrate, a resin substrate such as a bismaleimide-triazine resin substrate, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated in detail based on an Example and a comparative example, this invention is not limited to this. First, it demonstrates based on the Example and comparative example of a conductive adhesive film.

(Example 1)
1. Preparation of resin varnish Acrylic acid copolymer A (manufactured by Nagase ChemteX Corporation, SG-P3-DR, glass transition temperature 15 ° C., weight average molecular weight 850,000, acrylonitrile content 30% by weight, glycidyl as acrylic resin (Methacrylate content 3.0 wt%) 11.9 wt% and epoxy resin A (Nippon Kayaku Co., Ltd., EOCN-1020-80, equivalent 200 g / eq) 6.0 wt% as a curable resin, cyanate resin (Asahi Ciba, AroCy L-10) 1.4% by weight and flaky silver powder as conductive particles (DMC2 Japan, SF-86S, average particle size 3.0 μm, maximum particle size 30 μm or less) 30% %, 10% by weight of spherical silver powder A (manufactured by DMC2 Japan, SF-48, average particle size 5.0 μm, maximum particle size 30 μm or less), and silver 40% by weight (manufactured by Fukuda Metals Co., Ltd., AgXF301H, average particle size 5.0 μm, maximum particle size 30 μm or less), 0.1% by weight of an imidazole compound (1B2PZ, manufactured by Shikoku Kasei Kogyo Co., Ltd.) A silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., KBM403E) 0.6% by weight as an agent was dissolved in methyl ethyl ketone to obtain a resin varnish having a solid content of 61.1% by weight.

2. Production of conductive adhesive film The above-mentioned resin varnish was applied to a supporting substrate PET film (RL-07 (38), thickness 38 μm) with a comma coater and dried at 80 ° C. for 8 minutes to obtain a conductive adhesive film. .

3. Manufacture of Semiconductor Device The wafer was laminated on the back surface of a semiconductor element (thickness 300 μm) under the conditions of a temperature of 130 ° C., a linear pressure of 1.0 MPa, and a speed of 5 mm / second. Further, after laminating a dicing tape (FSN-40006, manufactured by Sumitomo Bakelite Co., Ltd.) at room temperature, the wafer with the conductive adhesive film was cut into 8.0 × 10.0 mm, and the dicing tape was peeled off to remove the semiconductor with the conductive adhesive film. Chip. This was thermocompression bonded to a 42 alloy lead frame with a pressurization time of 1 second, a temperature of 200 ° C., and a pressure of 1.0 MPa. Then, it sealed with the epoxy sealing material (EME-6300S) by Sumitomo Bakelite Co., Ltd., and obtained the semiconductor device (QFP, size 14mmx20mmx2mm).

(Example 2)
The procedure was the same as Example 1 except that the following acrylic resin was used.
Acrylic acid copolymer B (manufactured by Nagase ChemteX Corporation, SG-80HDR, glass transition temperature 10 ° C., weight average molecular weight 350,000, acrylonitrile content 20% by weight, glycidyl methacrylate content 1.0 % By weight) was used.

(Example 3)
The procedure was the same as Example 1 except that the following acrylic resin was used.
Acrylic acid copolymer C (manufactured by Nagase ChemteX Corporation, SG-600LBDR, glass transition temperature-31.4 ° C., weight average molecular weight 1,200,000, acrylonitrile content 6.0% by weight as acrylic resin Glycidyl methacrylate content 0% by weight) was used.

( Reference Example 4)
The procedure was the same as Example 1 except that the following acrylic resin was used.
As an acrylic resin, acrylic acid copolymer D (manufactured by Nagase ChemteX Corporation, SG-600, glass transition temperature 85 ° C., acrylonitrile content 0% by weight, glycidyl methacrylate content 0% by weight) was used.

(Example 5)
The procedure was the same as Example 1 except that the following curable resin was used.
Epoxy resin B (Japan Epoxy Resin, EP1100L, equivalent of 4,000 g / eq) was used as the curable resin.

(Example 6)
The same procedure as in Example 1 was conducted except that the following conductive particles were used.
Instead of the spherical silver powder, spherical copper powder (manufactured by Nippon Atomizing Co., Ltd., SF-Cu, average particle diameter 10 μm, maximum particle diameter 30 μm or less) was used.

(Example 7)
The same procedure as in Example 1 was performed except that the following were used without using the silver powder as the conductive particles.
The content of spherical silver powder B (manufactured by Fukuda Metals Co., Ltd., AgC-156I, average particle diameter of 2 to 3 μm, maximum particle diameter of 30 μm or less) was set to 40% by weight instead of the managed silver powder.

(Example 8)
Example 1 was performed except that the following were used without using flaky silver powder as conductive particles.
Instead of the flaky silver powder, the content of the spherical silver powder C (manufactured by Tokuhoku Chemical Laboratory Co., Ltd., AgF-5S, average particle size 4 to 6 μm, maximum particle size 30 μm or less) was set to 10% by weight.

(Example 10)
The procedure was the same as Example 1 except that the following curable resin was used.
Epoxy resin C (manufactured by Dainippon Ink and Chemicals, HP7200L, equivalent of 244 g / eq) was used as the curable resin.

(Comparative Example 1)
The same procedure as in Example 1 was performed except that the following resin was used instead of the acrylic resin.
Silicone modified polyimide resin instead of acrylic resin (2,2-bis [4- (4-aminophenoxy) phenyl] propane (0.15 mol) and α, ω-bis (3-aminopropyl) poly as diamine component Dimethylsiloxane (average molecular weight 837) (0.15 mol) and 4,4′-oxydiphthalic dianhydride (0.15 mol) and 3,3 ′, 4,4′-biphenyltetracarboxylic acid diacid as acid components A polyimide resin soluble in anisole obtained by synthesizing an anhydride (0.15 mol), Tg: 100 ° C., weight average molecular weight 50,000) was used.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that the following resin was used instead of the acrylic resin.
A phenoxy resin (manufactured by Tohto Kasei Co., Ltd., FX-280S, glass transition temperature 160 ° C., weight average molecular weight 20,000) was used in place of the acrylic resin.

The following evaluation was performed about the electroconductive adhesive film obtained by each Example and the comparative example. The evaluation contents are shown together with the evaluation items. The obtained results are shown in Table 1.
1. Initial adhesion After the conductive adhesive films obtained in each Example and Comparative Example were attached to a silicon wafer at 150 ° C., the chips were diced to a chip size of 4 mm × 4 mm using a dicing machine (Disco, DAD341). . Next, a 4 mm × 4 mm semiconductor element with a conductive adhesive film was chip mounted at a pressure bonding temperature of 160 ° C., a pressure of 10 MPa, and a pressure bonding time of 1.0 second, and the die shear strength was measured at room temperature to measure the initial adhesion. Each code is as follows.
A: The die shear strength exceeds 2.0 MPa.
○: Die shear strength is 1.5 to 2.0 MPa or less.
Δ: Die shear strength is 1.0 to less than 1.5 MPa.
X: Die shear strength is less than 1.0 MPa.

2. Volume resistance value The volume resistance value was determined by treating the conductive adhesive films obtained in each Example and Comparative Example at 180 ° C. for 1 hour, thermosetting them, cutting them to a width of 10 mm, and a length of 60 mm. Volume resistance was measured with a milliohm meter. Each code is as follows.
A: Volume resistance value is 1.0 × 10 ⁻³ Ω · cm or less ○: Volume resistance value exceeds 1.0 × 10 ⁻³ and less than 1.0 × 10 ⁻⁴ Ω · cm Δ: Volume resistance value is 1.0 × 10 ⁻⁴ or more, less than 1.0 × 10 ⁻⁵ Ω · cm ×: Volume resistance value is 1.0 × 10 ⁻⁵ Ω · cm or more

3. Adhesiveness Adhesiveness was evaluated by the adhesive strength during heating at 240 ° C.
The conductive adhesive films obtained in each Example and Comparative Example were further cured at 180 ° C. for 1 hour. After curing, the die shear strength during heating at 240 ° C. was measured using a push-pull gauge. Each code is as follows.
A: Die shear strength during heating exceeds 0.4 MPa B: Die shear strength during heating is 0.2 to 0.4 MPa or less Δ: Die shear strength during heating is less than 0.1 to 0.2 MPa.
X: Die shear strength during heating is less than 0.1.

4). Workability Workability was evaluated by the shape of the conductive adhesive film when the conductive adhesive film obtained in each Example and Comparative Example was cut into 100 mm × 100 mm, bent in half, and pressed at a pressure of 98 hPa. . Each code is as follows.
A: No breakage or the like.
○: Partially broken or the like, but practically usable.
(Triangle | delta): There exists a fracture etc. partially and it cannot be used practically.
X: There is a break or the like.

5. Existence of cutting waste The 4 mm x 4 mm conductive element with conductive adhesive film used for initial adhesion is peeled off from the expanded sheet, and one line parallel to the orientation flat and one line perpendicular to the orientation flat are observed with an optical microscope. Observed and counted the cutting waste protruding from the dicing line. Each code is as follows.
A: No cutting waste at all.
○: Although cutting waste is partially present, it can be used practically.
(Triangle | delta): There exists a cutting waste partially and it cannot be used practically.
X: There is cutting waste as a whole.

6). Breaking elongation The breaking elongation was determined by treating the conductive adhesive films obtained in each Example and Comparative Example at 180 ° C. for 1 hour, thermosetting them, cutting them to a width of 10 mm, and a length of 120 mm. The elongation at break was measured with Tensilon RTC-1250A (Orientec Co., Ltd.). Each code is as follows.

7). Preservability Each conductive adhesive film was left at room temperature for 720 hours. Then, it evaluated by peak top temperature using the scanning scanning calorimeter (Seiko Instruments company make, DSC6000), and was set as storability data.
A: Peak top temperature does not change.
○: The temperature change at the peak top is less than 5 ° C.
(Triangle | delta): The temperature change of a peak top is 5 degreeC or more and less than 8 degreeC.
X: The temperature change of the peak top is 8 degreeC or more.

8). Heat resistance Heat resistance was evaluated based on the thermal decomposition temperature of the conductive adhesive films obtained in each example and comparative example using a simultaneous thermothermogravimetric measuring apparatus (TG / DTA6200, manufactured by Seiko Instruments Inc.). . Each code is as follows.
(Double-circle): The thermal decomposition temperature of 5 weight% exceeds 350 degreeC.
○: The thermal decomposition temperature of 5% by weight is 320 to 350 ° C. or less.
(Triangle | delta): The thermal decomposition temperature of 5 weight% is less than 300-320 degreeC.
X: The thermal decomposition temperature of 5 weight% is less than 300 degreeC.

9. Reflow resistance Five same packages as the semiconductor devices obtained by the above-mentioned examples and comparative examples were produced. Each package was allowed to absorb moisture for 12 hours in a constant temperature and humidity chamber having a temperature and humidity of 85 ° C./85% RH, respectively. Solder reflow was performed by applying IR reflow at 230 ° C. for 10 seconds, and the peeled state was observed with an ultrasonic flaw detector. It was expressed as “Good number of samples / Evaluation number”.

As is apparent from Table 1, Examples 1 to 3, 5 to 8, and 10 had low volume resistance values and excellent initial adhesion. Therefore, it was shown that it is conductive and can be bonded at a low temperature.
Moreover, Examples 1-3, 6, and 7 were excellent in adhesiveness, and were excellent also in connection reliability.
In addition, Examples 1, 2, and 5 to 7 were excellent in workability.
Moreover, Examples 1-3 and 6-8 , 10 were excellent also in heat resistance.

It is sectional drawing which shows typically an example of the semiconductor device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Semiconductor element 3 Conductive adhesive film 4 Support member

Claims (6)

A conductive adhesive film composed of a resin composition containing a thermoplastic resin and silver powder as conductive particles,
The thermoplastic resin is an acrylic acid copolymer having acrylic acid and / or methacrylic acid ester as an essential copolymerization component,
The glass transition temperature of the thermoplastic resin is −10 to 50 ° C.,
The content of the silver powder is 60 to 90% by weight of the whole resin composition,
Furthermore, the breaking elongation after the hardening process of the said conductive adhesive film is 2% or more, The conductive adhesive film characterized by the above-mentioned.   The conductive adhesive film according to claim 1, wherein the resin composition further contains a curable resin. The conductive adhesive film according to claim 2 , wherein the acrylic acid copolymer contains a compound having a nitrile group. The conductive adhesive film according to claim 2 or 3 , wherein the acrylic acid copolymer contains a compound having an epoxy group. Conductive adhesive film according to any one of claims 1 to 4 volume resistivity of the conductive adhesive film is less than 10 ^-3 Ω · cm. Via a conductive adhesive film according to any one of claims 1 to 5, the semiconductor device characterized by a semiconductor element, and the support member are joined.

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