JP2018098272A - Paste-like adhesive composition, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paste-like adhesive composition superior in metal adhesion.SOLUTION: A paste-like adhesive composition of the present invention comprises: metal particles which are sintered to form particle-coupling structures when subjected to a heat treatment; and a resin having a decomposition start temperature of 40°C or higher and 250°C or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a paste adhesive composition and an electronic device.

  Until now, various developments have been made as die bonding materials for semiconductor chips. As this type of technology, the technology described in Patent Document 1 can be cited. According to this document, it is described that, as a die attach material, gold powder and ester alcohol are used and sintered under pressure and pressure conditions, so that sintering can be performed at a relatively low temperature.

JP 2007-324523 A

  As a result of investigation by the present inventor, it has been found that the die bond material described in the above-mentioned document 1 has room for improvement in terms of metal adhesion to the back surface metal plating chip.

The present inventor has focused on the sinterability with respect to the back surface metal plating chip, that is, the property of metal adhesion, and as a result of investigation, as a result of using a resin having a predetermined decomposition start temperature, It was found that it can be improved.
Based on such knowledge, further studies were conducted based on the temperature range in which the metal particles are sintered by heat treatment to form a particle connection structure. The inclusion of the adhesive composition found that the sintering of the metal particles was promoted to improve the metal adhesion to the back surface metal plating chip, and the present invention was completed.

According to the present invention,
Metal particles that cause sintering by heat treatment to form a particle-linked structure;
And a resin having a decomposition start temperature of 40 ° C. or higher and 250 ° C. or lower.

Moreover, according to the present invention,
An electronic device comprising a sintered product of the paste adhesive composition is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the paste-form adhesive composition excellent in metal adhesiveness and an electronic device using the same can be provided.

It is sectional drawing which shows the semiconductor device which concerns on this embodiment. FIG. 8 is a cross-sectional view showing a modification of the semiconductor device shown in FIG. 1.

  Hereinafter, embodiments will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

The outline | summary of the paste adhesive composition of this embodiment is demonstrated.
The paste adhesive composition of the present embodiment can include metal particles that cause sintering by heat treatment to form a particle connection structure, and a resin having a decomposition start temperature of 40 ° C. or higher and 250 ° C. or lower.

In this embodiment, the temperature (sintering temperature) at the time of sintering of metal particles can be set to 200 ° C. or higher and 350 ° C. or lower when silver particles are used, for example.
Although the detailed mechanism is not clear, in the sintering process of metal particles, a resin having a decomposition start temperature in the sintering temperature region is vaporized and increased in volume, thereby pressing the metal particles and sintering between the metal particles. It is considered that the sinterability of the metal particles can be improved because the resin itself is suppressed from remaining after sintering. Moreover, it is guessed that the paste adhesive composition of this embodiment improves the sinterability with respect to a back surface metal plating chip | tip, ie, metal adhesiveness, by such a mechanism.

  The paste-like adhesive composition of the present embodiment can improve the sinterability (metal adhesion) to a back surface metal plating chip such as a back surface silver plating chip or back surface gold plating chip in pressureless sintering, for example. it can. That is, the paste adhesive composition of this embodiment can be used as an adhesive for pressureless sintering. By using such a paste-like adhesive composition sintered product, a highly reliable electronic device structure can be realized.

  Hereinafter, each component of the paste adhesive composition of this embodiment is demonstrated.

(Metal particles)
In the present embodiment, the metal particles contained in the composition cause sintering by heat-treating the paste-like adhesive composition to form a particle connection structure. That is, in the adhesive layer obtained by heating the paste adhesive composition, the metal particles are fused to each other. Thereby, about the adhesive bond layer obtained by heating a paste-form adhesive composition, the heat conductivity, electroconductivity, the adhesiveness to a base material, a semiconductor element, a heat sink, etc. can be improved.

  The metal particles include, for example, one or more selected from the group consisting of Ag (silver), Au (gold), and Cu (copper). From the viewpoint of improving the sinterability of the metal particles and effectively improving the thermal conductivity and conductivity of the adhesive layer obtained using the thermally conductive composition, silver particles can be included as the metal particles. In addition to the above materials, the metal particles can contain metal components other than silver, gold, and copper for the purpose of, for example, promoting sintering or reducing costs.

  It is preferable that the silver particle of this embodiment contains the silver coating resin particle by which the surface of the silicone resin particle was coat | covered with silver. Moreover, the silver particle of this embodiment may contain the said silver covering resin particle and silver powder. In the embodiment, silver powder is not silver-coated particles but metal particles made of silver.

  The silver-coated resin particles are, for example, particles (silicone resin particles) made of an organopolysiloxane obtained by polymerizing an organochlorosilane such as methylchlorosilane, trimethyltrichlorosilane, dimethyldichlorosilane, etc., coated with silver. In addition, the surface of a silicone resin particle composed of a silicone resin having a basic skeleton with a structure obtained by further three-dimensionally cross-linking this organopolysiloxane is also included.

Moreover, it is possible to introduce various functional groups into the structure of the silicone resin particles. Examples of functional groups that can be introduced include epoxy groups, amino groups, methoxy groups, phenyl groups, carboxyl groups, hydroxyl groups, alkyl groups, vinyl groups, Examples include, but are not limited to, mercapto groups.
In the present embodiment, other low stress modifiers may be added to the silicone resin particles as long as the characteristics are not impaired. Examples of other low stress modifiers that can be used in combination include butadiene styrene rubber, butadiene acrylonitrile rubber, polyurethane rubber, polyisoprene rubber, acrylic rubber, fluororubber, liquid organopolysiloxane, and liquid synthetic rubber such as liquid polybutadiene. However, it is not limited to these.

  In the present specification, “the surface of the silicone resin particles is coated with silver” means that the silver covers at least a part of the surface of the silicone resin particles. For this reason, it is not limited to an aspect covering the entire surface of the silicone resin particles, for example, an aspect covering the entire surface when viewed from a specific cross section, or an aspect covering a specific region of the surface (for example, And a mode in which a metal layer made of silver is formed on the surface of the silicone resin particles. However, from the viewpoint of further effectively suppressing the heat cycle property of the obtained adhesive layer, it is preferable to cover the entire surface when viewed from at least a specific cross section, and further to cover the entire surface. preferable.

Moreover, the silver particle of this embodiment can reduce the specific gravity as the whole silver particle by including a silver covering resin particle in this way, and can suppress the sedimentation in a composition, etc. Therefore, the uniformity as a paste adhesive composition can be improved.
Moreover, it becomes possible to give elasticity as an adhesive layer to be obtained by including silver-coated resin particles in the silver particles. Thereby, the heat cycle property as an adhesive bond layer can be improved.

  The shape of the metal particles is not particularly limited, and examples thereof include a spherical shape and a flake shape. In the present embodiment, the metal particles can include spherical particles. Thereby, the sinterability of the metal particles can be improved. Moreover, it can contribute to the improvement of the uniformity of sintering. Further, from the viewpoint of reducing the cost, it is possible to adopt an embodiment in which the metal particles include flaky particles. For example, the metal particles according to the present embodiment can include flaky silver particles. Furthermore, from the viewpoint of improving the balance between cost reduction and sintering uniformity, the metal particles may include both spherical particles and flaky particles. In the present embodiment, the shape of the silver-coated resin particles may be spherical. On the other hand, the shape of the silver powder may be either spherical or flaky.

  In the present embodiment, the lower limit value of the silver coating amount in the silver-coated resin particles is not particularly limited, but may be, for example, 20% by weight or more, or 30% by weight or more with respect to 100% by weight of the total of silver and silicone resin particles. It may be 40% by weight or more. Thereby, the sinterability of silver particles can be improved. The upper limit value of the silver coating amount in the silver-coated resin particles is not particularly limited. For example, the upper limit value of the silver-coated resin particles may be 95% by weight or less or 93% by weight or less with respect to 100% by weight of the total of silver and silicone resin particles It is good also as 90 weight% or less. Thereby, sedimentation in the composition of silver particles can be suppressed.

  In the present embodiment, the lower limit of the specific gravity of the silver-coated resin particles is not particularly limited, but may be, for example, 1.2 or more, 1.5 or more, or 2.0 or more. Thereby, since the sintered body of silver particles can be obtained stably, manufacturing process stability can be improved. On the other hand, the upper limit value of the specific gravity of the silver-coated resin particles is not particularly limited, but may be, for example, 8.0 or less, 7.0 or less, or 6.5 or less. Thereby, the uniformity of the paste-form adhesive composition obtained can be improved.

In the present embodiment, the lower limit of the average particle diameter (D ₅₀ ) of the silver-coated resin particles is not particularly limited, but may be, for example, 0.5 μm or more, 1.5 μm or more, or 2.0 μm or more. On the other hand, the upper limit of the average particle diameter (D ₅₀ ) of the silver-coated resin particles is not particularly limited, but may be, for example, 16 μm or less, 12 μm or less, or 8 μm or less.

The average particle diameter (D ₅₀ ) of the metal particles is, for example, not less than 0.8 μm and not more than 20 μm. When the average particle diameter of the silver particles is equal to or more than the lower limit, it is possible to suppress an excessive increase in the specific surface area and suppress a decrease in thermal conductivity due to contact thermal resistance. Moreover, it becomes possible to improve the sinterability between silver particles because the average particle diameter of silver particles is below the said upper limit. Further, from the viewpoint of improving the dispensing property of the paste adhesive composition, the average particle size (D ₅₀ ) of the metal particles is more preferably 1 μm or more and 18 μm or less, and preferably 1.2 μm or more and 16 μm or less. Particularly preferred. The average particle diameter of the silver particles of the present embodiment may be an average particle diameter of a mixture of silver-coated resin particles and silver powder.

Here, in the present embodiment, the lower limit value of the particle size D ₅₀ (average particle size (D ₅₀ )) at the time of 50% accumulation in the volume-based cumulative distribution of silver powder is preferably 0.3 μm or more, for example. And more preferably 0.8 μm or more, and particularly preferably 1.2 μm or more. By setting it to the above lower limit value or more, thermal conductivity can be improved. The upper limit of the particle diameter D ₅₀ at 50% accumulation in a cumulative distribution of volume-based silver powder, for example, preferably at 10μm or less, more preferably 7μm or less, in particular it is 5μm or less preferable. By setting it to the upper limit or less, the sinterability between silver particles can be improved, and the uniformity of sintering can be improved.

The average particle diameter (D ₅₀ ) of the metal particles can be determined by performing particle image measurement using, for example, a flow type particle image analyzer FPIA (registered trademark) -3000 manufactured by Sysmex Corporation. More specifically, the particle diameter of the metal particles can be determined by measuring the volume-based median diameter using the above apparatus.
In this embodiment, the average particle diameter (D ₅₀ ), maximum particle diameter, and specific gravity of the metal particles can be evaluated as physical property values of all metal particle components including the metal-coated resin particles.

  The maximum particle size of the silver particles is not particularly limited, but may be, for example, 8 μm or more and 30 μm or less, more preferably 9 μm or more and 25 μm or less, and particularly preferably 10 μm or more and 20 μm or less. This makes it possible to more effectively improve the balance between the uniformity of sintering and the dispensing property.

  In the present embodiment, the lower limit of the content of the silver-coated resin particles in the entire silver particles is, for example, preferably 1% by weight or more, more preferably 5% by weight or more, and 10% by weight or more. Is more preferable. Thereby, it becomes easy to reduce the specific gravity as the whole silver particle, and the dispersibility of the particle in a composition can be improved. On the other hand, the upper limit of the content of the silver-coated resin particles in the entire silver particles is preferably 98% by weight or less, more preferably 95% by weight or less, and still more preferably 90% by weight or less. . Thereby, the heat conductivity and electroconductivity as an adhesive bond layer can be improved further.

  In the present embodiment, the lower limit value of the silver particle content in the paste adhesive composition is not particularly limited, but may be, for example, 10% by volume or more, 20% by volume or more, and 30% by volume or more. It is good. On the other hand, the upper limit of the content of silver particles in the paste adhesive composition is not particularly limited, but may be, for example, 90% by volume or less, 80% by volume or less, or 70% by volume or less. . The volume content of the silver particles of the present embodiment may be the volume content of a mixture of silver-coated resin particles and silver powder.

  In the present embodiment, the weight ratio of the silver component to the entire silver particles is, for example, 30% by weight or more, preferably 40% by weight or more, and more preferably 50% by weight or more. By making the weight ratio of a silver component more than said value, the heat conductivity and electroconductivity as an adhesive bond layer can be improved further. On the other hand, the weight ratio of the silver component to the entire silver particles is, for example, 99% by weight or less, preferably 98% by weight or less, and more preferably 97% by weight or less. By setting the weight ratio of the silver component to the above value or less, the specific gravity of the silver particles in the composition can be easily lowered and the dispersibility of the particles can be improved. The silver component of this embodiment may be a silver component in a mixture of silver-coated resin particles and silver powder.

  The specific gravity of the silver particles is, for example, 2 or more, preferably 2.5 or more, and more preferably 3 or more. By setting the specific gravity of the silver particles to the above value or more, the thermal conductivity and conductivity as the adhesive layer can be further improved. The specific gravity of the silver particles is, for example, 10 or less, preferably 9 or less, and more preferably 8 or less. By making the specific gravity of the silver particles not more than the above value, the dispersibility of the particles can be improved. The specific gravity of the silver particles of this embodiment may be the specific gravity of a mixture of silver-coated resin particles and silver powder.

  The content of the metal particles in the paste adhesive composition is, for example, preferably 1% by weight or more, and more preferably 5% by weight or more with respect to the entire paste adhesive composition. Thereby, it becomes possible to improve the sinterability of metal particles and contribute to the improvement of thermal conductivity and conductivity. On the other hand, the ratio of the content of the metal particles in the paste adhesive composition is, for example, preferably 95% by weight or less, particularly 90% by weight or less, based on the entire paste adhesive composition. preferable. Thereby, it can contribute to improvement of the application | work workability | operativity of the whole paste-form adhesive composition, the mechanical strength of an adhesive bond layer, etc.

  In addition, in this specification, content with respect to the whole paste-form adhesive composition refers to content with respect to the whole component except a solvent of paste-form adhesive compositions, when a solvent is included.

In the present embodiment, not only silver particles but also other metal particles may be used, such as the above-mentioned metal-coated resin particles or a combination of metal particles and metal-coated particles.
In addition, the silver particle which concerns on this embodiment may contain metal components other than silver, such as gold | metal | money and copper, for the purpose of promoting sintering or cost reduction, for example.

(resin)
The paste adhesive composition of this embodiment can contain a resin having a decomposition start temperature of 40 ° C. or higher and 250 ° C. or lower. In the present embodiment, the decomposition start temperature can be calculated by measuring the weight loss in a temperature range of 40 ° C. to 500 ° C. in a nitrogen atmosphere. In this specification, the decomposition start temperature is the temperature at which the thermal decomposition rate reaches 10%.
In the present embodiment, the upper limit value of the decomposition start temperature of the resin in a nitrogen atmosphere may be, for example, 250 ° C. or lower, 240 ° C. or lower, or 230 ° C. or lower. Further, the lower limit of the decomposition start temperature of the resin in a nitrogen atmosphere may be, for example, 40 ° C. or higher, 80 ° C. or higher, or 100 ° C. or higher.

  The resin according to the present embodiment can be thermally decomposed at a lower temperature than, for example, cellulose resins such as ethyl cellulose and methyl sesulose. This inventor examined the thermal decomposition start temperature and 99% thermal decomposition temperature in nitrogen atmosphere about the following cellulose resins. Ethylcellulose has a thermal decomposition starting temperature of about 300 ° C. or higher, and a 99% thermal decomposition temperature is higher than about 450 ° C. Methylsesulose has a thermal decomposition onset temperature of about 290 ° C., and a 99% thermal decomposition temperature is higher than about 450 ° C.

  As resin which concerns on this embodiment, resin comprised by the polymer which has a structural unit derived from an acrylic compound can be included, for example. Examples of such a resin include methacrylic resin (manufactured by Sekisui Plastics Co., Ltd., Techpolymer IBM-2).

  Moreover, the upper limit of the glass transition temperature (Tg) of the resin according to the present embodiment may be, for example, 120 ° C. or less, preferably 100 ° C. or less, and more preferably 80 ° C. or less. Thereby, the metal adhesiveness with respect to a back surface metal plating chip | tip can be improved. On the other hand, the lower limit of the glass transition temperature (Tg) is not particularly limited, but may be, for example, 50 ° C. or higher. This improves the handleability.

  In addition, the upper limit value of the 99% thermal decomposition temperature of the resin according to this embodiment is, for example, 450 ° C. or less, preferably 400 ° C. or less, and more preferably 390 ° C. or less. Thereby, metal adhesiveness can be improved. On the other hand, the lower limit of the 99% pyrolysis temperature may be, for example, 250 ° C. or higher, preferably 300 ° C. or higher, and more preferably 350 ° C. or higher. Thereby, the sinterability of a metal particle and the metal adhesiveness with respect to a back surface metal plating chip | tip can be improved.

The lower limit of the weight average molecular weight (Mw) of the resin according to the present embodiment may be, for example, 10 ³ or more, preferably 5.0 × 10 ³ or more, and more preferably 10 ⁴ or more. On the other hand, the upper limit of the weight average molecular weight (Mw) is, for example, 10 ⁷ or less, preferably 10 ⁶ or less, and more preferably 5.0 × 10 ⁵ or less. By setting to such a range, the flow characteristics of the paste adhesive composition and the dispersibility of the metal particles can be improved.

  The lower limit of the content of the resin according to this embodiment is, for example, 0.01% by weight or more, preferably 0.05% by weight or more, and more preferably, with respect to the entire paste-like adhesive composition. It is 0.1% by weight or more. Thereby, the metal adhesiveness with respect to a back surface metal plating chip | tip can be improved. On the other hand, the upper limit of the content of the resin according to this embodiment is, for example, 5% by weight or less, preferably 3% by weight or less, and more preferably 1% by weight or less. Thereby, the sinterability of the metal particles can be improved.

(Compound that polymerizes by heating)
The paste-like adhesive composition of the present embodiment can usually contain, as a dispersion medium, a component that can be a monomer or a binder for dispersing the above-described metal particles.
That is, the paste adhesive composition of this embodiment can contain, as the dispersion medium, for example, a compound that disperses metal particles and polymerizes by heating.

  The compound that is polymerized by heating is selected from, for example, a compound (α-1) having only one radical polymerizable double bond in the molecule and a compound (α-2) having only one epoxy group in the molecule. 1 type, or 2 or more types can be included. Thereby, when the paste-like adhesive composition is heat-treated, it becomes possible to polymerize the compound in a linear form. For this reason, the uniformity of sintering and the balance of dispensing properties can be improved. Among those exemplified above, it is more preferable that at least the compound (α-1) is included from the viewpoint of reducing the volume resistivity of the adhesive layer obtained by using the paste adhesive composition.

  The compound (α-1) having only one radical polymerizable double bond in the molecule is, for example, a compound having only one (meth) acryl group in the molecule, a compound having only one vinyl group in the molecule, One or more selected from compounds having only one allyl group in the molecule, compounds having only one maleimide group in the molecule, and compounds having only one maleic acid group in the molecule may be included. . In the present embodiment, it is more preferable to include at least a compound having only one (meth) acryl group in the molecule from the viewpoint of more effectively improving the uniformity of sintering. As a compound which has only one (meth) acryl group in a molecule | numerator, the (meth) acrylic acid ester etc. which have only one (meth) acryl group in a molecule | numerator can be included, for example.

  The (meth) acrylic acid ester contained in the compound (α-1) having only one radical polymerizable double bond in the molecule is, for example, a compound represented by the following formula (1) and the following formula (2): 1 type, or 2 or more types selected from the compound represented by these can be included. Thereby, the uniformity of sintering can be improved more effectively.

In the above formula _{(1), R 11} is hydrogen or a methyl _{group, R 12} is a monovalent organic group having 1 to 20 carbon atoms containing OH groups. R ₁₂ may contain one or more of an oxygen atom, a nitrogen atom, and a phosphorus atom. The compound represented by the above formula (1) is not particularly limited. For example, 1,4-cyclohexanedimethanol monoacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl Methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-methacryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydro Phthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl phthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid, 2-acryloyl Carboxymethyl ethyl acid phosphate, and 2-methacryloyloxypropyl ethyl can Acid containing one or more selected from phosphates. In the present embodiment, for example, a compound having a cyclic structure in R ₁₂ as exemplified by 1,4-cyclohexanedimethanol monoacrylate, or a compound in R ₁₂ as exemplified by 2-methacryloyloxyethyl succinic acid. The case where a compound containing a carboxyl group is contained in can be adopted as an example of a preferred embodiment.

In formula (2), R ₂₁ is hydrogen or a methyl group, and R ₂₂ is a monovalent organic group having 1 to 20 carbon atoms that does not contain an OH group. R ₂₂ may contain one or more of an oxygen atom, a nitrogen atom, and a phosphorus atom. The compound represented by the above formula (2) is not particularly limited. For example, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, isoamyl acrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl acrylate , N-lauryl methacrylate, n-tridecyl methacrylate, n-stearyl acrylate, n-stearyl methacrylate, isostearyl acrylate, ethoxydiethylene glycol acrylate, butoxydiethylene glycol methacrylate, methoxytriethylene glycol acrylate, 2-ethylhexyl diethylene glycol acrylate, methoxypolyethylene glycol Acrylate, methoxypolyether Lenglycol methacrylate, methoxydipropylene glycol acrylate, cyclohexyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxy polyethylene glycol acrylate, nonylphenol ethylene oxide modified acrylate, phenylphenol Ethylene oxide modified acrylate, isobornyl acrylate, isobornyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoethyl methacrylate quaternized, glycidyl methacrylate, and neope It can include one or more selected from the chill glycolic acrylate benzoate. In this embodiment, for example, as exemplified by phenoxyethyl methacrylate and cyclohexyl methacrylate, a compound containing a cyclic structure in R ₂₂ , as exemplified by 2-ethylhexyl methacrylate, n-lauryl acrylate, and n-lauryl methacrylate. The case where R ₂₂ contains a compound in which R ₂₂ is a linear or branched alkyl group can be employed as an example of a preferred embodiment.

  In the present embodiment, from the viewpoint of improving the balance of various properties such as uniformity of sintering and mechanical strength, it is included in the compound (α-1) having only one radical polymerizable double bond in the molecule. For example, the (meth) acrylic acid ester may include both a compound represented by the above formula (1) and a compound represented by the above formula (2). On the other hand, the compound (α-1) may contain only one of the compound represented by the formula (1) and the compound represented by the formula (2).

  Compounds having only one epoxy group in the molecule (α-2) are, for example, n-butyl glycidyl ether, versatic acid glycidyl ester, styrene oxide, ethylhexyl glycidyl ether, phenyl glycidyl ether, butylphenyl glycidyl ether, and cresyl One or more selected from glycidyl ether can be included. Among these, from the viewpoint of improving the balance of sintering uniformity, thermal conductivity, conductivity, and the like, an example of a preferred embodiment that includes at least cresyl glycidyl ether is given.

  The compound that is polymerized by heating preferably does not include, for example, a compound having two or more radical polymerizable double bonds in the molecule or a compound having two or more epoxy groups in the molecule. Thereby, it becomes possible to polymerize the said compound in linear form, and it can contribute to the improvement of the uniformity of sintering. On the other hand, the said compound may contain the compound which has two or more radically polymerizable double bonds in a molecule | numerator, and the compound which has two or more epoxy groups in a molecule | numerator. When a compound having two or more radically polymerizable double bonds in the molecule or a compound having two or more epoxy groups in the molecule is included, the combined content exceeds 0% by weight of the total compound. It is preferable to make it not more than wt%. Thereby, since it can suppress that many three-dimensional crosslinked structures are integrated in the superposition | polymerization structure which a compound produces | generates, it becomes possible to suppress that the sintering of silver particles is prevented by a three-dimensional crosslinked structure.

  The content of the compound polymerized by heating contained in the paste adhesive composition is preferably, for example, 5% by weight or more, more preferably 8% by weight or more, based on the entire paste adhesive composition. It is preferably 10% by weight or more. Thereby, the uniformity of sintering can be improved more effectively. Moreover, it can also contribute to the improvement of the mechanical strength and the like of the adhesive layer. On the other hand, the content of the compound contained in the paste adhesive composition is preferably, for example, 20% by weight or less, more preferably 18% by weight or less with respect to the entire paste adhesive composition. It is preferably 15% by weight or less. Thereby, it becomes possible to contribute to the improvement of the sinterability of silver particles.

(Curing agent)
The paste adhesive composition can contain, for example, a curing agent. The curing agent is not particularly limited as long as it accelerates the polymerization reaction of the compound that is polymerized by heating. Thereby, the polymerization reaction of the said compound can be accelerated | stimulated and it can contribute to the improvement of the mechanical characteristic obtained using a paste adhesive composition.

  On the other hand, in the present embodiment, from the viewpoint of improving the balance of sintering uniformity, thermal conductivity, conductivity, etc., for example, an embodiment in which a curing agent is not included in the paste adhesive composition may be employed. it can. The phrase “the paste adhesive composition does not contain a curing agent” means, for example, a case where the content of the curing agent is 0.01 parts by weight or less with respect to 100 parts by weight of the compound polymerized by heating.

  The curing agent can include, for example, a compound having a tertiary amino group. Thereby, for example, when the compound that is polymerized by heating contains a compound having an epoxy group in the molecule, it is possible to accelerate the polymerization of the compound in a linear form. Examples of the compound having a tertiary amino group include tertiary amines such as benzyldimethylamine (BDMA), imidazoles such as 2-methylimidazole and 2-ethyl-4-methylimidazole (EMI24), pyrazole, 3,5 -Pyrazoles such as dimethylpyrazole and pyrazoline, triazoles such as triazole, 1,2,3-triazole, 1,2,4-triazole and 1,2,3-benzotriazole, imidazoline, 2-methyl-2-imidazoline And imidazolines such as 2-phenylimidazoline, and one or more selected from these may be included. Thereby, for example, when the compound that is polymerized by heating contains a compound having an epoxy group in the molecule, the homo ring-opening polymerization of the epoxy group can be selectively promoted. Among these, from the viewpoint of improving the balance of sintering uniformity, thermal conductivity, conductivity, and the like, an example of a preferable embodiment that includes at least an imidazole is given.

  The curing agent can include, for example, a radical polymerization initiator. Thereby, for example, when the compound that is polymerized by heating contains a compound having a radical polymerizable double bond in the molecule, it is possible to promote the polymerization of the compound. Examples of the radical polymerization initiator include octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, oxalic acid peroxide, 2,5-dimethyl -2,5-di (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl-1-methylethylperoxy 2-ethylhexanoate, tert-hexylperoxy 2-ethylhexanoate, tert-butylper Oxy 2-ethylhexanoate, m-toluyl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, acetyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, cumene hydroperoxide De may include dicumyl peroxide, tert- butyl perbenzoate, p-chlorobenzoyl peroxide, and one or more selected from cyclohexanone peroxide.

  Content of the hardening | curing agent contained in a paste-form adhesive composition can be 25 weight part or less with respect to 100 weight part of compounds which superpose | polymerize, for example by heating. In particular, when the compound includes a compound (α-1) having only one radical polymerizable double bond in the molecule, the curing agent for 100 parts by weight of the compound from the viewpoint of improving the uniformity of sintering. The content of is preferably 5 parts by weight or less, more preferably 3 parts by weight or less, and particularly preferably 1 part by weight or less. Moreover, content of the hardening | curing agent contained in a paste-form adhesive composition can be 0 weight part or more with respect to 100 weight part of said compounds. From the viewpoint of improving the mechanical properties of the paste adhesive composition, for example, the content of the curing agent with respect to 100 parts by weight of the compound can be 0.1 parts by weight or more.

(Polymerization inhibitor)
The paste adhesive composition can contain, for example, a polymerization inhibitor. As the polymerization inhibitor, a compound that suppresses the polymerization reaction of the compound contained in the paste adhesive composition is used. Thereby, the storage characteristic of a paste-form adhesive composition can be improved more. The polymerization inhibitor is not particularly limited, but, for example, hydroquinones exemplified by hydroquinone, p-tert-butylcatechol, and mono-tert-butylhydroquinone, hydroquinone monomethyl ether, and phenols exemplified by di-p-cresol , P-benzoquinone, naphthoquinone, and quinones exemplified by p-toluquinone, and one or more selected from copper salts exemplified by copper naphthenate.

  The content of the polymerization inhibitor in the paste adhesive composition is preferably 0.0001 part by weight or more, for example, 0.001 part by weight or more with respect to 100 parts by weight of the compound polymerized by heating. More preferred. Thereby, it becomes possible to contribute to the improvement of the uniformity of sintering. Moreover, the storage characteristic of a paste-form adhesive composition can be improved more effectively. On the other hand, the content of the polymerization inhibitor in the paste adhesive composition is preferably 0.5 parts by weight or less, for example, 100 parts by weight or less, and 0.1 parts by weight or less. More preferred. Thereby, the mechanical strength etc. of an adhesive bond layer can be improved.

  The paste adhesive composition according to the present embodiment can contain a solvent, for example. Thereby, the fluidity | liquidity of a paste-form adhesive composition can be improved and it can contribute to the improvement of workability | operativity. The solvent is not particularly limited, but for example, 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 mono Propyl 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, Izo Alcohols such as palmityl alcohol, isostearyl alcohol, lauryl alcohol, ethylene glycol, propylene glycol, butylpropylene triglycol or glycerin; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, diacetone alcohol (4-hydroxy-4-methyl- Ketones such as 2-pentanone), 2-octanone, isophorone (3,5,5-trimethyl-2-cyclohexen-1-one) or diisobutylketone (2,6-dimethyl-4-heptanone); ethyl acetate, acetic acid Butyl, diethyl phthalate, dibutyl phthalate, acetoxyethane, methyl butyrate, methyl hexanoate, methyl octoate, methyl decanoate, methyl cellosolve acetate, ethylene glycol Esters such as nobutyl ether acetate, propylene glycol monomethyl ether acetate, 1,2-diacetoxyethane, tributyl phosphate, tricresyl phosphate or tripentyl phosphate; tetrahydrofuran, dipropyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene Ethers such as glycol dibutyl ether, propylene glycol dimethyl ether, ethoxyethyl ether, 1,2-bis (2-diethoxy) ethane, or 1,2-bis (2-methoxyethoxy) ethane; 2- (2-butoxyethoxy) ethane acetate Ester ethers such as 2-ether ether such as 2- (2-methoxyethoxy) ethanol; toluene, xylene, n-paraffin, isopara Hydrocarbons such as tin, dodecylbenzene, turpentine oil, kerosene or light oil; nitriles such as acetonitrile or propionitrile; amides such as acetamide or N, N-dimethylformamide; low molecular weight volatile silicone oil, or One or more selected from volatile organic modified silicone oils can be included.

Next, an example of the electronic device according to the present embodiment will be described.
The electronic device of this embodiment includes a sintered product of the paste adhesive composition.
As an example of the electronic device of this embodiment, a semiconductor device 100 as shown in FIG.

  FIG. 1 is a cross-sectional view showing a semiconductor device 100 according to this embodiment. The semiconductor device 100 according to the present embodiment includes a base material 30 and a semiconductor element 20 mounted on the base material 30 via a die attach layer 10 (adhesive layer) that is a heat treatment body of a paste adhesive composition. It is equipped with. The semiconductor element 20 and the base material 30 are electrically connected through, for example, a bonding wire 40 or the like. Further, the semiconductor element 20 is sealed with, for example, a sealing resin 50. Although the film thickness of the die attach layer 10 is not specifically limited, For example, they are 5 micrometers or more and 100 micrometers or less.

  In the example shown in FIG. 1, the base material 30 is, for example, a lead frame. In this case, the semiconductor element 20 is mounted on the die pad 32 (30) via the die attach layer 10. Further, the semiconductor element 20 is electrically connected to the outer lead 34 (30) through, for example, the bonding wire 40. The base material 30 which is a lead frame is composed of, for example, a 42 alloy, Cu frame. The base material 30 may be an organic substrate or a ceramic substrate. As the organic substrate, for example, a substrate known to those skilled in the art to which an epoxy resin, a cyanate resin, a maleimide resin or the like is applied is suitable. Further, the surface of the substrate 30 may be coated with silver or the like in order to improve the adhesiveness with the paste adhesive composition.

The planar shape of the semiconductor element 20 is not particularly limited, but is rectangular, for example. In the present embodiment, for example, a rectangular semiconductor element 20 having a chip size of 0.5 mm □ or more and 15 mm □ or less can be employed.
As an example of the semiconductor device 100 according to the present embodiment, for example, a semiconductor chip 20 using a rectangular large chip having sides of 5 mm or more can be cited.

  In this embodiment, the die attach layer 10 is comprised by the above-mentioned paste-form adhesive composition. Here, the metal particles in the paste-like adhesive composition can include the above silver-coated resin particles. Thereby, moderate flexibility can be imparted to the die attach layer 10.

FIG. 2 is a cross-sectional view showing a modification of the semiconductor device 100 shown in FIG.
In the semiconductor device 100 according to this modification, the base material 30 is, for example, an interposer. For example, a plurality of solder balls 52 are formed on the other surface of the base material 30 that is an interposer opposite to the one surface on which the semiconductor element 20 is mounted. In this case, the semiconductor device 100 is connected to another wiring board via the solder balls 52.

Next, a method for manufacturing the semiconductor device 100 will be described.
The semiconductor device 100 according to the present embodiment can be manufactured as follows, for example. First, the semiconductor element 20 is mounted on the base material 30 through the paste adhesive composition of the present embodiment. Next, the paste adhesive composition is heated. As a result, the semiconductor device 100 is manufactured.

  As an outline of the manufacturing method of the semiconductor device 100 in the present embodiment, for example, after applying the paste adhesive composition on the substrate 30, the semiconductor element 20 is mounted on the coating film made of the paste adhesive composition. Is done.

  Specifically, first, a coating film is formed by applying a paste-like adhesive composition on the substrate 30. The method for applying the paste adhesive composition is not particularly limited, and examples thereof include a dispensing method, a printing method such as screen printing, and an ink jet method.

  Next, you may implement the process of drying a coating film. Thereby, the film thickness uniformity of a coating film can be improved. The drying conditions are not particularly limited as long as an excess volatile component is volatilized to form a dry film with suppressed tack.

  Next, the semiconductor element 20 is mounted on the coating film formed on the substrate 30.

  Next, the coating film made of the paste adhesive composition is heat-treated. At this time, the heat treatment may be performed while the semiconductor element 20 is fixed and pressed, but the heat treatment may be performed on the semiconductor element 20 in a non-pressurized state (self-weight only).

  The paste adhesive composition of this embodiment is excellent in metal adhesion to the back surface metal plating chip. For this reason, the paste adhesive composition of this embodiment interposes the said paste adhesive composition between the 1st member (for example, base material 30) and the 2nd member (for example, semiconductor element 20). The laminated body can be used in a step of heating without pressure. Even in such a pressureless sintering step, the metal adhesion to the back surface metal plating chip can be improved.

  By the heat treatment, sintering occurs in the metal particles in the coating film made of the paste adhesive composition, and a particle connection structure is formed between the metal particles. As a result, the die attach layer 10 is formed on the substrate 30.

  In this embodiment, by performing heat treatment while applying pressure to the paste-like adhesive composition, the sinterability of the metal particles can be further improved, and the formation of the particle connection structure can be promoted.

As an example of the heat treatment of the manufacturing method according to the present embodiment, for example, heating is performed for a certain period of time at a temperature T ₁ of less than 200 ° C., followed by heating for a certain period of time at a temperature T ₂ of 200 ° C. or more. The first heat treatment and the second heat treatment can be performed. T ₁ can be, for example, 120 ° C. or more and less than 200 ° C. T ₂ can be, for example, 200 ° C. or higher and 350 ° C. or lower. In this example, the processing time for the first heat treatment temperatures T ₁ may be, for example, be at least 20 minutes 90 minutes or less. Further, the processing time of the second heat treatment temperature T ₂ may be, for example, 180 minutes or less 30 minutes or more.

  In the paste-like adhesive composition of the present embodiment, the lower limit value of the sintering start temperature may be, for example, 120 ° C. or higher, 150 ° C. or higher, or 200 ° C. or higher. The upper limit of the sintering start temperature is not particularly limited, but may be, for example, 250 ° C. or lower, 240 ° C. or lower, or 230 ° C. or lower.

On the other hand, in this embodiment, after raising the temperature from 25 ° C. to a temperature T ₃ of 200 ° C. or higher without stopping the temperature rise, the paste-like adhesive composition is heated for a certain time under the temperature condition of the temperature T _3. The object may be heat treated. In this case, treats before reaching the 200 ° C. of the heating step as the first heat treatment, to handle the process of heat treatment at a temperature T ₃ was heated to a temperature T ₃ from 200 ° C. as a second heat treatment Can do. T ₃ can be, for example, 200 ° C. or higher and 350 ° C. or lower.

In this embodiment, in an example of the manufacturing method in which heat treatment is performed while applying pressure to the paste adhesive composition, for example, after heating for a certain period of time at a temperature T ₁ of less than 200 ° C., the paste adhesive composition it is possible to perform processing by predetermined time heating at a temperature of the temperature T ₂ of the 200 ° C. or higher while applying a pressure P ₁ against the object. T ₁ can be, for example, 80 ° C. or higher and lower than 200 ° C. P ₁ can be set to, for example, 1 MPa or more and less than 50 MPa. T ₂ can be, for example, 200 ° C. or higher and 350 ° C. or lower. Further, the processing time of the second heat treatment temperature T _2, for example may be 60 minutes or less than 0.5 minutes.
Next, the semiconductor element 20 and the base material 30 are electrically connected using the bonding wire 40. Next, the semiconductor element 20 is sealed with a sealing resin 50. In the present embodiment, for example, the semiconductor device 100 can be manufactured as described above.

In the present embodiment, for example, a heat sink may be bonded to the semiconductor device. In this case, for example, the heat sink can be bonded to the semiconductor device via an adhesive layer obtained by heat-treating the paste adhesive composition.
The heat sink can be bonded as follows, for example. First, a heat sink is bonded to the semiconductor device via the paste adhesive composition described above. Next, the paste adhesive composition is heat-treated. The heat treatment for the paste adhesive composition can be performed, for example, in the same manner as the step of forming the die attach layer 10 by heat treating the paste adhesive composition in the method for manufacturing the semiconductor device 100 described above. Thereby, sintering occurs in the metal particles in the paste-like adhesive composition, a particle connection structure is formed between the metal particles, and an adhesive layer for adhering the heat sink is formed. In this way, the heat sink can be bonded to the semiconductor device.

  It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.

  Next, examples of the present invention will be described.

[Preparation of paste adhesive composition]
A paste adhesive composition was prepared for each example and each comparative example. The paste adhesive composition was obtained by mixing each component uniformly according to the formulation shown in Table 1.
The details of the components shown in Table 1 are as follows. Moreover, the compounding ratio of each component in Table 1 indicates the compounding ratio (parts by weight) of each component with respect to the entire paste adhesive composition.

(Metal particles)
Silver particles 1: Silver powder (manufactured by DOWA Electronics), AG2-1C, spherical, average particle diameter (D ₅₀ ) 1.7 μm)
Silver particles 2: Silver powder (Fukuda Metal Foil Powder Industry Co., Ltd., AgC-271B, flake shape, average particle diameter (D ₅₀ ) 2.4 μm)
(Dispersion medium)
Dispersion medium 1: 1,4-cyclohexanedimethanol monoacrylate (Nippon Kasei Co., Ltd., CHDMMA, monofunctional acrylic)
Dispersion medium 2: Phenoxyethyl methacrylate (manufactured by Kyoeisha Chemical Co., Ltd., light ester PO, monofunctional acrylic)
Dispersion medium 3: butyl propylene triglycol (manufactured by Nippon Emulsifier Co., Ltd., BFTG)
(resin)
Resin 1: Methacrylic resin (manufactured by Sekisui Plastics Co., Ltd., Techpolymer IBM-2, decomposition start temperature (10% thermal decomposition temperature): about 227 ° C., 99% thermal decomposition temperature: about 380 ° C., glass transition temperature: 72 ° C, weight average molecular weight Mw: 7.5 × 10 ⁵ )
(Curing agent)
Hardener 1: Dicumyl peroxide (manufactured by Kayaku Akzo Co., Ltd., Perkadox BC, peroxide)

For each example, the coating film obtained by applying the obtained paste adhesive composition was increased from 25 ° C. to 250 ° C. at a rate of temperature increase of 5 ° C./min in a nitrogen atmosphere having a residual oxygen concentration of less than 1000 ppm. After heating, heat treatment was performed at 250 ° C. for 2 hours. As a result, the silver particles in the coating film caused sintering and formed a particle connection structure.
On the other hand, when the paste-like adhesive composition of each comparative example was used, the particle connection structure was not formed.

[Evaluation]
The paste-like adhesive composition obtained above was evaluated based on the following items.

(Die shear strength after moisture absorption)
A silicon chip having a 2 mm × 2 mm × 0.350 mm back surface plated with Au was mounted on an Ag-plated copper frame via the paste adhesive composition obtained above. Next, the silver particles in the paste-like adhesive composition are sintered in an oven to form an adhesive layer under a sintering condition of 25 minutes to 230 ° C. for 30 minutes and 230 ° C. for 60 minutes, Sample 1 was created.
A 2 mm × 2 mm × 0.350 mm back-sided Ag-plated silicon chip was mounted on an Ag-plated copper frame via the paste adhesive composition obtained above. Next, the silver particles in the paste-like adhesive composition are sintered in an oven to form an adhesive layer under a sintering condition of 25 minutes to 230 ° C. for 30 minutes and 230 ° C. for 60 minutes, Sample 2 was created.
The obtained samples 1 and 2 were subjected to moisture absorption treatment under the conditions of 85 ° C. and humidity 85% for 72 hours, and then the die shear strength after moisture absorption at 260 ° C. was measured (unit: N / 1 mm ² ).

(Volume resistivity)
On the glass epoxy resin substrate, the obtained paste-like adhesive composition was applied in a strip shape having a width of 1 cm and a length of 10 cm so as to have a thickness of 100 μm, and a temperature of 25 ° C. in a nitrogen atmosphere having a residual oxygen concentration of less than 1000 ppm. After heating from 250 to 250 ° C. at a heating rate of 5 ° C./min, heat treatment was performed at 250 ° C. for 2 hours to form an adhesive layer. The resistance value of the obtained adhesive layer was measured by the 4-terminal method, and the volume resistivity was calculated. The unit was Ω · cm.

  From the results of Table 1, it was found that according to Examples 1 to 20, a paste-like adhesive composition giving an adhesive layer excellent in metal adhesion was obtained.

DESCRIPTION OF SYMBOLS 100 Semiconductor device 10 Die attach layer 20 Semiconductor element 30 Base material 32 Die pad 34 Outer lead 40 Bonding wire 50 Sealing resin 52 Solder ball

Claims (13)

Metal particles that cause sintering by heat treatment to form a particle-linked structure;
A paste adhesive composition comprising: a resin having a decomposition start temperature of 40 ° C. or higher and 250 ° C. or lower. The paste-like adhesive composition according to claim 1,
A paste-like adhesive composition comprising a dispersion medium containing a compound that polymerizes upon heating, in which the metal particles are dispersed. A paste adhesive composition according to claim 2,
The said compound superposed | polymerized by heating is a paste-form adhesive composition containing the compound which has only one (meth) acryl group in a molecule | numerator, or the compound which has only one epoxy group in a molecule | numerator. The paste-like adhesive composition according to any one of claims 1 to 3,
A paste adhesive composition, wherein the resin is composed of a polymer having a structural unit derived from an acrylic compound. A paste adhesive composition according to any one of claims 1 to 4,
The paste adhesive composition whose glass transition temperature (Tg) of the said resin is 120 degrees C or less. A paste adhesive composition according to any one of claims 1 to 5,
A paste adhesive composition, wherein the resin has a 99% thermal decomposition temperature of 250 ° C or higher and 450 ° C or lower. A paste adhesive composition according to any one of claims 1 to 6,
The resin composition has a weight average molecular weight of 10 ³ or more and 10 ⁷ or less. A paste adhesive composition according to any one of claims 1 to 7,
A paste-like adhesive composition in which the metal particles include silver particles. A paste adhesive composition according to claim 8,
A paste-like adhesive composition in which the silver particles include flakes. The paste-like adhesive composition according to any one of claims 1 to 9,
The average particle diameter _{D 50} of the metal particles is 0.8μm or more 20μm or less, paste adhesive composition. A paste-like adhesive composition according to any one of claims 1 to 10,
The paste adhesive composition whose sintering start temperature is 120 degreeC or more and 250 degrees C or less. The paste-like adhesive composition according to any one of claims 1 to 11,
A paste adhesive composition used in a step of heating without pressure to a laminate in which the paste adhesive composition is interposed between a first member and a second member.   An electronic device comprising the sintered product of the paste adhesive composition according to any one of claims 1 to 12.

Images