TW201930527A - Pasty adhesive composition and semiconductor device - Google Patents

Abstract

The pasty adhesive composition of an embodiment according to the present invention comprises an epoxy resin and silver particles and, upon a heat treatment, comes to have connected-silver-particle structures each formed therein from two or more of the silver particles with the disappearance of the interfaces therebetween. When the pasty adhesive composition is applied to a copper lead frame in a thickness of 25±10 [mu]m, subsequently a bare silicon wafer having a length of 2 mm and a width of 2 mm is placed on the pasty adhesive composition to obtain a stack, and the stack is heated in the air from 25 DEG C to 175 DEG C over 30 minutes and then held at 175 DEG C for 30 minutes to thereby obtain a cured layer, then the bare silicon and the copper lead frame have a strength in shearing across the cured layer, as measured at a temperature of 260 DEG C, of 5.0-15.0 MPa.

Description

Paste-like adhesive composition and semiconductor device

The present invention relates to a paste-like adhesive composition and a semiconductor device.

Conventionally, two types of paste-like adhesive compositions of a bonding type and a sintering type have been used in the paste-like adhesive composition for bonding of various components of semiconductor devices and electrical and electronic parts.

Adhesive paste-type adhesive composition is a composition in which conductive metal particles such as silver particles are dispersed in a liquid thermosetting resin, and the adhesive composition is crimped by hardening of the heated resin. Metal particles ensure electrical and thermal conductivity.
In the adhesive paste-like adhesive composition, the adhesiveness and adhesion to the adherend are exhibited by the curing of the liquid thermosetting resin. Furthermore, since the paste-like adhesive composition shrinks due to hardening, the frequency of contact between the metal particles is higher than before the hardening, and the contact points between the metal particles are increased. Thereby, the hardened | cured material of a slurry-form adhesive composition shows electrical conductivity and thermal conductivity.
In the adhesive paste-like adhesive composition, the cured thermosetting resin is adhered to the adherend. Therefore, such an adhesive paste-like adhesive composition has adhesion not only to metals such as copper, silver, gold, nickel, and palladium, but also to adherends other than metals such as bare silicon. On the other hand, in the adhesive paste-like adhesive composition, metal particles are in contact with each other via a cured product of a thermosetting resin. Therefore, compared with the sintered type, the adhesive paste-like adhesive composition of the type may have a smaller contact area with silver particles and may have poor thermal conductivity.

The sintered paste-like adhesive composition is a composition in which metal particles are dispersed in a volatile dispersion medium. In the adhesive composition, the dispersion medium is volatile by heat treatment, and conduction is ensured by sintering the metal particles. .
In the sintered paste-like adhesive composition, the metal particles dispersed in the sintered paste-like adhesive composition are volatilized by heating to agglomerate. Furthermore, the interface between the metal particles in the agglomerate disappears by the action of heat, in other words, the metal particles sinter to form a metal particle connection structure. In the sintered paste-like adhesive composition, not all dispersion media will volatilize, and a small amount of monomers contained in the dispersion medium will not volatilize and remain. The residual monomers play a role in adhering the metal particle bonding structure to the adherend. . In addition, due to the volatilization of the dispersion, the connecting structure of the metal particles and the adherend are attracted and bonded. When the adherend is a metal such as silver or gold, the interface between the metal particles and the adherend disappears and is firmly adhered.
The sintered paste-like adhesive composition can exhibit a higher thermal conductivity than the adhesive by forming a metal particle connection structure. On the other hand, when a sintered paste-like adhesive composition is used as an adhesive, although there is a monomer between the metal particle connection structure formed by heating and the adherend, the monomer may be present in a trace amount. Adhesion between the metal particle-connected structure and the adherend cannot be sufficiently obtained. In addition, the adhesion between the adhered body and the metal particle connection structure is affected by the type or combination of the metal material and the metal particles that constitute the adhered body. Therefore, when the compatibility of the material of the adhered body and the metal particles is poor, The adhesion between the implant and the metal particle connecting structure is weak, and peeling occurs between these.

For example, Patent Document 1 describes an adhesive paste-like adhesive composition. Patent Document 1 describes that a specific acrylic resin, a radical initiator, a specific silver fine particle, a specific silver powder, and a solvent are excellent in heat dissipation properties, and a semiconductor element can be well bonded to a metal substrate. The semiconductor is then made of a thermosetting resin composition.

Further, for example, Patent Document 2 describes a sintered paste-like adhesive composition. Patent Document 2 describes a method having excellent adhesion to a substrate, solder wettability, migration resistance, oxidation resistance, and electrical bonding properties by including a specific alloy powder, glass powder, and an organic vehicle. Slurry.

Patent Document 1: Japanese Patent Application Publication No. 2014-074132 Patent Document 2: Japanese Patent Application Publication No. 06-139813

The present inventors investigated reliability such as connection reliability, mounting reliability, and chip-Chip thermal diffusion coefficient for a semiconductor device in which lead frames such as copper, silver, and gold are connected to bare silicon through a paste-like adhesive composition. Sex. As a result, it was found that the heat dissipation property of the thermosetting resin composition for semiconductor bonding described in Patent Document 1 is insufficient, and the paste described in Patent Document 2 has insufficient adhesion to the adherend.
Therefore, an object of the present invention is to provide a paste-like adhesive composition that can be preferably used for manufacturing a semiconductor device that has improved both reliability and heat dissipation in a balanced manner.

In order to obtain a conductive paste having suitable adhesion to both bare silicon and metal, and a cured product having excellent thermal conductivity, the present inventors considered making a mixed paste type that combines conventional bonding type and sintering type. Adhesive composition. As a result, it was found that the above problems can be solved by using the following paste-like adhesive composition: the above-mentioned paste-like adhesive composition contains an epoxy resin and silver particles, and the silver particles form a silver particle connection structure by heat treatment, The paste-like adhesive composition was applied to a copper lead frame so that the coating thickness became 25 ± 10 μm, and then a bare silicon wafer having a length of 2 mm × width 2 mm was placed on the paste-like adhesive composition. A laminated body was obtained, and then the laminated body was heated from a temperature of 25 ° C. to 175 ° C. under an atmospheric environment for 30 minutes, and further held at 175 ° C. for 30 minutes to obtain a hardened body. The shear strength of the bare silicon and the copper circuit is within a specific numerical range. Specifically, it was found that by using such a composition, it is possible to suppress the peeling of the cured product and the adherend of the paste-like adhesive composition. Therefore, the mixed-type paste-like adhesive composition can exhibit suitable adhesion to various materials such as bare silicon and metal, just like the paste-type paste-like adhesive composition.
In addition, the mixed paste-like adhesive composition has a structure in which silver particles are connected, and similarly to the sintered paste-like adhesive composition, it can improve heat dissipation.
Based on the above, the present inventors found that when the shear strength of the bare silicon and copper circuit is within a specific numerical range, reliability and heat dissipation can be improved, and a mixed paste-like adhesive composition, which is the present invention, has been completed. .

According to the present invention, a paste-like adhesive composition is provided, comprising:
Epoxy resin; and silver particles, and the silver particles form a silver particle connection structure through heat treatment,
This paste-like adhesive composition was coated on a copper lead frame so that the coating thickness became 25 ± 10 μm, and then a bare silicon wafer having a length of 2 mm × width of 2 mm was placed on the paste-like adhesive composition. The laminated body was obtained, and then the laminated body was heated from the temperature of 25 ° C. to 175 ° C. for 30 minutes in the atmospheric environment, and further maintained at 175 ° C. for 30 minutes to obtain a hardened body. The shear strength between the bare silicon of the hardened body and the copper lead frame is 5.0 MPa to 15.0 MPa.

In addition, according to the present invention, a semiconductor device is provided, including:
A substrate; and a semiconductor element loaded on the substrate through an adhesive layer,
The said adhesive layer is formed by hardening the said slurry-like adhesive composition.

The present invention provides a paste-like adhesive composition that improves the reliability and heat dissipation of a semiconductor device using the paste-like adhesive composition in a balanced manner.

The above-mentioned objects and other objects, features, and advantages are further apparent by the preferred embodiments described below and the accompanying drawings.

Hereinafter, this embodiment will be described using preferred drawings. In all drawings, the same components are denoted by the same reference numerals, and descriptions thereof are omitted.

The paste-like adhesive composition of this embodiment contains an epoxy resin and silver particles, and a silver particle connection structure in which a plurality of interfaces between the above-mentioned silver particles disappears is formed by heat treatment. The adhesive composition was applied to a copper lead frame so that the coating thickness became 25 ± 10 μm. Next, a bare silicon wafer having a length of 2 mm × width 2 mm was placed on the paste-like adhesive composition to obtain a laminated body. When the laminated body was heated from the temperature of 25 ° C. to 175 ° C. in the atmospheric environment for 30 minutes, and further maintained at 175 ° C. for 30 minutes to obtain a hardened body, the bare silicon sandwiched with the hardened body was measured at a temperature of 260 ° C. The shear strength with the copper circuit is 5.0 MPa to 15.0 MPa.

In order to improve the reliability of the paste-like adhesive composition such as close contact reliability, mounting reliability and other heat dissipation properties such as Chip-Chip thermal diffusion coefficient, the inventors considered making a combination of the conventional adhesive type and sintered type. Type paste-like adhesive composition. As a result, it was found that when the paste-like adhesive composition forming the silver particle-linked structure is laminated with the bare silicon wafer and the copper lead frame through the paste-like adhesive composition and hardened by heat treatment, the shear strength is preferably as follows: Within a specific numerical range. Thereby, when the paste-like adhesive composition is hardened, the heat dissipation property can be improved by forming a silver particle connection structure. Furthermore, it is possible to improve heat dissipation within a specific numerical range by shear strength, and to improve reliability such as close contact reliability and structural reliability.
As described above, the paste-like adhesive composition of this embodiment can improve the reliability and heat dissipation of a semiconductor device using the paste-like adhesive composition in a balanced manner.

In this embodiment, for example, by properly selecting the raw material components contained in the paste-like adhesive composition, a silver particle connection structure is formed, and the shear strength can be controlled within a specific numerical range. Specific control factors include: appropriately selecting the shape and content of silver particles; appropriately selecting the particle size distribution of silver particles such as average particle diameter, specific surface area, and tapping degree; containing epoxy resin as a main agent; controlling main The balance between the content of the agent and the content of the silver particles; the slurry-like adhesive composition during heating and hardening does not contain a monomer which does not cause a hardening reaction at all and only volatilizes.
Although the detailed mechanism is uncertain, it is speculated that by appropriately controlling the above factors, epoxy resin remains at the interface of silver particles. Thereby, the hardened | cured material of an epoxy resin is interposed between a silver particle connection structure and a to-be-adhered body, and can thereby set a shear strength in a specific range. Moreover, when there are too many epoxy resins in the silver particle interface of a slurry-like adhesive composition, there exists a problem that the silver particle connection structure cannot be formed. However, since the epoxy resin is uniformly dispersed at the interface of the silver particles, the paste-like adhesive composition of this embodiment can form a silver particle connection structure.
Furthermore, it is estimated that by appropriately controlling the above factors, the silver particles are appropriately attracted to each other. Thereby, a silver particle connection structure can be formed suitably. When the content of the epoxy resin in the paste-like adhesive composition is as large as that of the paste-like adhesive composition, if the silver particles attract each other too much, the paste-like adhesive composition may cause Excessive hardening. Thereby, the interface of the hardened | cured material of a slurry-like adhesive composition and a to-be-adhered body was damaged by shrinkage, and the shear strength did not fall in the required numerical range. However, since the silver particles of the paste-like adhesive composition of the present embodiment are properly attracted to each other, the paste-like adhesive composition is not damaged by shrinkage.

Hereinafter, each raw material component of the slurry-like adhesive composition of this embodiment is demonstrated.

(Silver particles)
The slurry-like adhesive composition of this embodiment contains silver particles.
In the paste-like adhesive composition of the present embodiment, the epoxy resin as a main agent described later is hardened, and the silver particles generate attraction, and the silver particles collide with each other. Thereby, the interface between the silver particles disappears, and a silver particle connection structure with high thermal conductivity is formed, thereby improving heat dissipation.
That is, the paste-like adhesive composition of the present embodiment is, for example, a mixed paste-like adhesive that forms a silver particle connection structure by appropriately controlling factors such as the properties of the silver particles with respect to the paste-type paste-like adhesive composition.剂 组合 物。 Composition.
In this embodiment, the silver particle connection structure means a structure in which silver particles collide with each other and the interface disappears.

The silver particle connection structure is not limited. For example, the lower limit value of the Chip-Chip thermal diffusion coefficient measured by a gold-plated silicon wafer, for example, 0.27 cm ² / sec or more is a preferable silver particle connection structure, and 0.30 cm ² / sec or more for better coupling structure of silver particles become 0.35cm ² / sec or more for the silver particles further preferred coupling structure becomes 0.37cm ² / sec or more for the silver particles are preferably the further link structure.
The upper limit of the Chip-Chip thermal diffusion coefficient measured with a gold-plated silicon wafer is not limited, and may be, for example, 1.0 cm ² / sec or less.
In addition, as a method for measuring the Chip-Chip thermal diffusion coefficient using a gold-plated silicon wafer, for example, the following method can be used: two gold-plated silicon wafers are prepared as follows: The gold-plated silicon wafer is a silicon wafer having a length of 10 mm × width 10 mm × thickness of 350 μm in order For those who are plated with Ti, Ni, and Au, one of the silicon wafers is coated with a paste-like adhesive composition so that the thickness is 25 ± 10 μm, and another silicon wafer is laminated thereon, and then, 30 minutes are passed. After increasing the temperature from 25 ° C to 175 ° C, heat treatment was performed at a temperature of 175 ° C for 60 minutes to harden the paste-like adhesive composition as a hardened material. Then, the thermal diffusion coefficient of the following test piece was measured by a laser flash method. This test piece was formed by laminating a gold-plated silicon wafer, a cured product of a paste-like adhesive composition, and a gold-plated silicon wafer in this order.

The shape of the silver particles may specifically include a scale shape or a spherical shape. As the silver particle, for example, it is preferable to include at least a scale shape, and for example, it is more preferable to use a scale shape and a spherical shape together. That is, the silver particles are more preferably, for example, scaly silver particles and spherical silver particles in a scaly shape. This is preferable from the viewpoint that the silver particles appropriately attract each other.

The particle size distribution of the spherical silver particles and scaly silver particles in the present embodiment will be described below.

(Scaly silver particles)
The upper limit of the average particle size of the scaly silver particles is, for example, preferably 6.0 μm or less, more preferably 5.0 μm or less, even more preferably 4.0 μm or less, and still more preferably 3.0 μm or less, particularly preferably 2.5 μm or less. Thereby, silver particles are easily attracted to each other, and a silver particle connection structure can be appropriately formed. In addition, it is also preferable that the silver particles are not present at the interface between the paste-like adhesive composition and the adherend, and internal stress is generated at the interface, thereby suppressing the destruction of the paste-like adhesive composition.物 的 硬 物。 Hardened matter.
The lower limit of the average particle size of the scaly silver particles is, for example, preferably 0.5 μm or more, more preferably 0.7 μm or more, still more preferably 1.0 μm or more, and still more preferably 1.5 μm or more. This is preferable from the viewpoint of suppressing excessive attraction of silver particles to each other.

The lower limit of the specific surface area of scaly silver particles, for example, is preferably 0.40m ² / g or more, more preferably 0.60m ² / g or more, more preferably 0.80m ² / g or more, more preferably It is 1.00 m ² / g or more, particularly preferably 1.09 m ² / g or more.
In the conventional paste-like adhesive composition, only the hardening and shrinkage of the main agent makes it difficult for the scaly silver particles to attract each other, and it is difficult to form a silver particle connection structure. When the specific surface area is equal to or more than the above-mentioned lower limit value, the silver particles are easily attracted to each other, and a silver particle connection structure can be appropriately formed.
The upper limit of the specific surface area of the scaly silver particles may be, for example, 2.00 m ² / g or less, or 1.50 m ² / g or less.
When both scaly silver particles and spherical silver particles are included as the silver particles, for example, the specific surface area of the scaly silver particles is preferably larger than the specific surface area of the spherical silver particles. Thereby, silver particles can attract each other appropriately.

The upper limit value of the tapping degree of the scaly silver particles is, for example, preferably 5.4 g / cm ³ or less, more preferably 5.0 g / cm ³ or less, and still more preferably 4.5 g / cm ³ or less. With this, when both scaly silver particles and spherical silver particles are included, the spherical silver particles can be appropriately immersed in the gaps between the scaly silver particles. Therefore, the silver particles can be appropriately attracted to each other, and the epoxy resin can be appropriately left and dispersed at the interface of the silver particles.
In addition, as the lower limit of the tapping degree of the scaly silver particles, it may be 1.0 g / cm ³ or more, 2.0 g / cm ³ or more, or 3.0 g / cm ³ or more.

(Spherical silver particles)
In addition to the above-mentioned scaly silver particles, the silver particles of the present embodiment preferably include, for example, spherical silver particles. Thereby, spherical silver particles can be immersed in the gaps of the scaly silver particles in a state where the base agent and the monomer exist. Therefore, the epoxy resin is uniformly dispersed at the interface of the silver particles, and the silver particles can appropriately attract each other.

The lower limit of the average particle diameter of the spherical silver particles is, for example, preferably 0.1 μm or more, more preferably 0.4 μm or more, and still more preferably 0.7 μm or more. This can prevent the silver particles from attracting each other excessively.
The upper limit of the average particle diameter of the spherical silver particles is, for example, preferably 5.0 μm or less, more preferably 4.0 μm or less, even more preferably 3.0 μm or less, still more preferably 2.0 μm or less, and particularly preferably It is preferably 1.5 μm or less. Thereby, when both scaly silver particles and spherical silver particles are included, the spherical silver particles can be appropriately immersed between the scaly silver particles. Therefore, silver particles can attract each other appropriately.

The lower limit of the specific surface area of the spherical silver particles, for example, is preferably 0.30m ² / g or more, more preferably 0.50m ² / g or more, more preferably 0.70m ² / g or more, more preferably It is 0.90 m ² / g or more. Thereby, silver particles can attract each other appropriately.
Further, the upper limit of the specific surface area of spherical silver particles, for example, may be 2.10m ² / g or less, that can 1.60m ² / g or less.

When both scaly silver particles and spherical silver particles are included as the silver particles, the upper limit value of the content of the scaly silver particles in the silver particles is 100 parts by mass relative to the total of the scaly silver particles and the spherical silver particles, for example, It is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 40 parts by mass or less, and still more preferably 30 parts by mass or less. Thereby, the spherical silver particles are immersed in the gaps between the scaly silver particles, and the particles attract each other appropriately.
When both scaly silver particles and spherical silver particles are included as the silver particles, the lower limit of the content of the scaly silver particles in the silver particles is 100 parts by mass relative to the total of the scaly silver particles and the spherical silver particles For example, it is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, even more preferably 15 parts by mass or more, and still more preferably 20 parts by mass or more.
Thereby, an epoxy resin can be appropriately immersed in the interface of a silver particle.

The lower limit of the content of the silver particles in the paste-like adhesive composition is, for example, preferably 50 parts by mass or more, more preferably 60 parts by mass or more, based on 100 parts by mass of the paste-like adhesive composition. It is more preferably 70 parts by mass or more, still more preferably 80 parts by mass or more, and even more preferably 82 parts by mass or more. The gravity between the silver particles due to the hardening of the main agent is, for example, smaller than the gravity between the silver particles due to the volatilization of the monomer. However, when the content of the silver particles is equal to or more than the above-mentioned lower limit value, even when the gravity between the particles is small, it is possible to appropriately form a silver particle bonding structure without volatilizing the contained components of the slurry-like adhesive composition.
The upper limit value of the content of the silver particles in the paste-like adhesive composition is, for example, preferably 90 parts by mass or less, and more preferably 87 parts by mass or less with respect to 100 parts by mass of the paste-like adhesive composition. Thereby, the epoxy resin appropriately remains and is dispersed at the interface of the silver particles.

(Epoxy resin)
The paste-like adhesive composition of this embodiment contains at least an epoxy resin such as an epoxy oligomer and an epoxy polymer as a main agent.
The paste-like adhesive composition of the present embodiment may further contain, for example, a resin other than an epoxy resin. Specific examples of the resin other than the epoxy resin include acrylic resins such as acrylic oligomers and acrylic polymers; and allyl resins such as allyl oligomers and allyl polymers.
The slurry-like adhesive composition of this embodiment hardens and shrinks due to the hardening of the main agent. By this hardening shrinkage, it is possible to generate a gravity between the silver particles and form a silver particle connection structure. Therefore, heat dissipation can be improved.
The epoxy resin can react with a hardening agent described later to harden and shrink. In addition, for example, when an epoxy monomer is contained as a monomer, an epoxy monomer is introduced to cause a curing reaction of the epoxy resin.
In addition, the acrylic resin can be hardened and shrunk by being polymerized by a radical polymerization initiator described later. In addition, for example, when an acrylic monomer is contained as a monomer, the acrylic monomer is introduced to polymerize the acrylic resin.
As with all acrylic resins, allyl resins can be hardened and shrunk by being polymerized by a radical polymerization initiator to be described later. In addition, an acrylic resin, an acrylic monomer, and an allyl monomer are introduced to polymerize the allyl resin.
In this embodiment, among polymers, those having a weight average molecular weight of less than 10,000 are represented as oligomers, and those having a weight average molecular weight of 10,000 or more are represented as polymers. In addition, resin means including an oligomer and a polymer.

〔Epoxy resin〕
As the epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule can be used.
Specific examples of the epoxy resin include triphenol methane type epoxy resins; hydrogenated bisphenol A type liquid epoxy resins; and bisphenol F type liquid epoxy resins such as bisphenol-F-glycidyl ether. Resin; o-cresol novolac epoxy resin, etc. As the epoxy resin, one or a combination of two or more of the specific examples can be used. As the epoxy resin, in the above specific examples, it is preferable to include a hydrogenated bisphenol A type liquid epoxy resin or a bisphenol F type liquid epoxy resin, and it is more preferable to include a bisphenol F type liquid epoxy resin. Thereby, it is possible to improve the operability of the slurry-like adhesive composition and uniformly apply the slurry-like adhesive composition, thereby improving reliability. Moreover, it is also preferable from the viewpoint of being able to form a suitable silver particle connection structure by appropriately hardening and shrinking a paste-like adhesive composition, and improving heat dissipation. Furthermore, it is also preferable from the viewpoint of an epoxy resin remaining appropriately and dispersed at the interface of silver particles.

〔Acrylic〕
As the acrylic resin, a liquid having two or more acrylic groups in one molecule can be used.
As the acrylic resin, specifically, those obtained by polymerizing or copolymerizing the acrylic monomer described in the monomer section described later can be used. Here, the method of polymerization or copolymerization is not limited, and a known method using a general polymerization initiator and a chain transfer agent such as solution polymerization can be used. In addition, as the acrylic resin, one kind may be used alone, or two or more kinds having different structures may be used.

[Allyl resin]
As the allyl resin, a liquid having two or more allyl groups in one molecule can be used.
Specific examples of the allyl resin include an allyl ester resin obtained by reacting a dicarboxylic acid, an allyl alcohol, and a compound having an allyl group.
Here, examples of the dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and horses. Maleic acid, fumaric acid, phthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, etc. As the dicarboxylic acid, one or a combination of two or more of the specific examples can be used.
Moreover, as a compound provided with the said allyl group, the polyether, polyester, polycarbonate, polyacrylate, polymethacrylate, polybutadiene, butadiene provided with the allyl group are mentioned specifically, Copolymer of acrylonitrile. As the compound having an allyl group, one or a combination of two or more of the above specific examples can be used.

The lower limit of the content of the main agent in the slurry-like adhesive composition is, for example, preferably 100 parts by mass or more, more preferably 3 parts by mass or more, based on 100 parts by mass of the slurry-like adhesive composition. It is more preferably 5 parts by mass or more. Thereby, the base agent can be appropriately hardened and shrunk to form a silver particle connection structure, and exhibit appropriate adhesion to the adherend. Therefore, the shear strength can be controlled within a numerical range described later.
The upper limit of the content of the main agent in the slurry-like adhesive composition is, for example, preferably 20 parts by mass or less, and more preferably 15 parts by mass based on 100 parts by mass of the slurry-like adhesive composition. Hereinafter, it is more preferably 14 parts by mass or less. Thereby, it is possible to suppress an excessive amount of the main agent from entering between the silver particles, and to prevent the formation of a silver particle coupling structure.

(Other ingredients)
The slurry-like adhesive composition of the present embodiment can contain, for example, a monomer, a radical polymerization initiator, a curing agent, a curing accelerator, a low stress agent, a silane coupling agent, and the like in addition to the above-mentioned raw material components.
Hereinafter, representative components will be described.

(monomer)
The slurry-like adhesive composition of this embodiment may further contain a monomer, for example. The monomer of this embodiment is one which is hardened and contracted by heat treatment.
Specific examples of such a monomer include an acrylic monomer, an epoxy monomer, and a maleimide monomer. As the monomer, one or a combination of two or more of the above specific examples can be used.
The acrylic monomer and the maleimide monomer are polymerized by a radical polymerization initiator described later.
The epoxy monomer can react with a hardening agent described later to harden and shrink.
In this embodiment, in order to form a structure in which silver particles are connected, and to control the shear strength within a specific numerical range, it is important not to contain a monomer that does not volatilize due to heat treatment polymerization. This makes it possible to increase the residual amount of the cured resin in the paste-like adhesive composition and improve the shear strength. Therefore, when an acrylic monomer or a maleimide monomer is contained as a monomer, the slurry-like adhesive composition further contains a radical polymerization initiator. When an epoxy monomer is included as a monomer, the paste-like adhesive composition contains a hardener.
Moreover, it is preferable to use the said main ingredient and a monomer together. Thereby, the molecular weight of the resin component such as the base agent and the monomer is reduced, and the dispersibility is improved, and a part of the monomer undergoes a hardening reaction and a part is volatilized, whereby the silver particles can be strongly attracted to each other.

[Acrylic monomer]
The acrylic monomer in this embodiment is a monomer having a (meth) acrylic group in its structure. Here, (meth) acrylic group means an acrylic group and a methacrylic group (methacrylate group).
The acrylic monomer in this embodiment may be a monofunctional acrylic monomer including only one (meth) acrylic group in its structure, or may be a polyfunctional acrylic monomer having two or more (meth) acrylic groups in its structure. Functional acrylic monomer.
In the present embodiment, the acrylic group includes an acrylate group.

As the monofunctional acrylic monomer, specifically, 2-phenoxyethyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth) acrylate , Tertiary butyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, n-lauryl (meth) acrylate, N-tridecyl (meth) acrylate, n-octadecyl (meth) acrylate, isostearyl (meth) acrylate, ethoxy diethylene glycol (meth) acrylate, butoxy Diethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, 2-ethylhexyl diethylene glycol (meth) acrylate, methoxypolyethylene glycol (methyl methacrylate) Base) acrylate, methoxydipropylene glycol (meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, phenoxy (methyl Based) ethyl acrylate, phenoxy diethylene glycol (meth) acrylate, phenoxy polyethylene glycol (meth) acrylic acid Ester, nonylphenol ethylene oxide modified (meth) acrylate, phenylphenol ethylene oxide modified (meth) acrylate, isomethacrylate (meth) acrylate, dimethyl (meth) acrylate Ethylamine, diethylamine ethyl (meth) acrylate, dimethylamine ethyl (meth) acrylate quaternary, propylene oxide (meth) acrylate, neopentyl glycol (meth) acrylate benzoin , 1,4-cyclohexanedimethanol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate , 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth) acryloxyethyl succinic acid, 2- (meth) acryloxyethyl hexahydrophthalate Formic acid, 2- (meth) acryloxy phthalic acid, 2- (meth) acryloxy-2-hydroxyethyl phthalic acid, and 2- (meth) acryloxyoxyacetic acid Esters, etc. As the monofunctional acrylic monomer, one kind or a combination of two or more kinds in the above specific examples can be used.
In this embodiment, (meth) acrylate means acrylate and methacrylate. Moreover, methacrylic acid means acrylic acid and methacrylic acid. (Meth) acrylfluorenyl means acrylfluorene and methacrylfluorenyl.

Specific examples of the polyfunctional acrylic monomer include ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and propoxylated bisphenol A di (methyl). Acrylate, hexane-1,6-diol bis (2-methyl (meth) acrylate), 4,4'-isopropylidene diphenol di (meth) acrylate, 1,3-butane Glycol di (meth) acrylate, 1,6-bis ((meth) propenyloxy) -2,2,3,3,4,4,5,5-octafluorohexane, 1,4 -Bis ((meth) acryloxy) butane, 1,6-bis ((meth) acryloxy) hexane, triethylene glycol di (meth) acrylate, neopentyl glycol di (Meth) acrylate, N, N'-bis (meth) propenyl ethylenediamine, N, N '-(1,2-dihydroxyethylene) bis (meth) acrylate or 1,4- Bis ((meth) acrylfluorenyl) pipe mouth wells, etc.

[Epoxy monomer]
The epoxy monomer in this embodiment is one having an epoxy group in its structure.
The epoxy monomer in this embodiment may be a monofunctional epoxy monomer having only one epoxy group in its structure, or a polyfunctional epoxy monomer having two or more epoxy groups in its structure. body.

As the monofunctional epoxy monomer, specifically, 4-tert-butylphenyl glycidyl ether, m-tolyl glycidyl ether, p-tolyl glycidyl ether, phenylglycidyl ether, Cresol-based glycidyl ether and the like. As the monofunctional epoxy monomer, one or a combination of two or more of the above specific examples can be used.

Specific examples of the polyfunctional epoxy monomer include bisphenol compounds such as bisphenol A, bisphenol F, and bisphenol or derivatives thereof; hydrogenated bisphenol A, hydrogenated bisphenol F, hydrogenated bisphenol, Cyclohexanediol, cyclohexanedimethanol and other diols with alicyclic structure or derivatives thereof; p-Butanediol, hexanediol, octanediol, nonanediol, decanediol and other aliphatic two Alcohols or derivatives thereof such as bifunctional ones; trifunctional groups with trihydroxyphenylmethane skeleton and aminephenol skeleton; p-phenol novolac resin, cresol novolac resin, phenol aralkyl resin, Bifunctional aralkyl resins, naphthol aralkyl resins, and the like are polyfunctional ones that undergo epoxidation. As the polyfunctional epoxy monomer, one or a combination of two or more of the above specific examples can be used.

[Cibutenediimine monomer]
The maleimide monomer of this embodiment is a maleimide ring having a maleimide ring in its structure.
The maleimide monomer of this embodiment may be a monofunctional maleimide monomer having only one maleimide ring in its structure, or it may be a structure A polyfunctional maleimide monomer having two or more maleimide rings.
Specific examples of the maleimide monomer include polytetramethylene ether glycol-bis (2-maleimide diimide acetate) and the like.

(Free radical polymerization initiator)
As a radical polymerization initiator, an azo compound, a peroxide, etc. can be used specifically ,. As the radical polymerization initiator, one or a combination of two or more of the specific examples can be used. As the radical polymerization initiator, in the above specific examples, for example, a peroxide is preferably used.

Specific examples of the peroxide include bis (1-phenyl-1-methylethyl) peroxide and 1,1-bis (1,1-dimethylethyl peroxide) cyclohexyl peroxide. Alkane, methyl ethyl ketone peroxide, cyclohexane peroxide, acetone peroxide, 1,1-di (tertiary-hexyl peroxide) cyclohexane, 1,1-di (tertiary-butyl) Peroxy) -2-methylcyclohexane, 1,1-di (tertiary-butyl peroxy) cyclohexane, 2,2-di (tertiary-butyl peroxy) butane, n-butyl -4,4-Di (tertiary-butylperoxy) valerate, 2,2-bis (4,4-di (tertiary-butylperoxy) cyclohexane) propane, hydrogen peroxide on methane , Dicumyl hydrogen peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydrogen peroxide, tertiary-butyl hydroperoxide, di (2-tertiary- Butyl isopropyl peroxide) benzene, dicumyl peroxide, 2,5-dimethyl-2,5-di (tertiary-butylperoxy) hexane, tertiary-butylisoperoxide Propylene, di-tertiary-butyl peroxide, 2,5-dimethyl 2,5-di (tertiary-butyl peroxy) hexyne, diisobutyl peroxide, di (3, 5,5-trimethylhexyl), Dilauryl peroxide, bis (3-methylbenzyl) peroxide, benzophenyl peroxide (3-methylbenzyl), dibenzyl peroxide, diperoxide (4 -Methyl benzamidine), di-n-propyl peroxydicarbonate, isopropyl peroxydicarbonate, di (2-ethylhexyl) peroxydicarbonate, di-secondary peroxydicarbonate- Butyl ester, cumene peroxide neodecanoate, 1,1,3,3-tetramethylbutyl neodecanoate, tertiary-hexyl neodecanoate, tertiary-butyrate neoheptanoate Ester, tertiary-hexyl peroxypivalate, 1,1-, 3,3-tetramethylbutyl peroxy-2-ethylhexanoate, 2,5-dimethyl-2,5, -di (2-Diethylhexanonium peroxide) hexane, tertiary-butyl peroxy-2-ethylhexanoate, tertiary-hexyl isopropyl monocarbonate, tertiary-peroxy maleic acid- Butyl ester, tertiary-butyl ester of 3,5,5-trimethylhexanoic acid, tertiary-butyl ester of isopropyl monocarbonate, tertiary-butyl ester of 2-ethylhexyl monocarbonate , Tertiary-hexyl benzoate, 2,5-dimethyl-2,5-di (benzylidene peroxy) hexane, tertiary-butyl ester acetone peroxide, peroxygen 3-methylbenzoic acid tertiary-butyl ester, tertiary-butyl peroxybenzoate, tertiary-butyl perallyl monocarbonate, 3,3 ', 4,4'-quad (tertiary -Butylperoxycarbonyl) benzophenone and the like. As the peroxide, one or a combination of two or more of the above specific examples can be used.

(hardener)
The slurry-like adhesive composition of the present embodiment preferably contains, for example, a hardener. Thereby, the epoxy resin and the epoxy monomer can be hardened and contracted to aggregate silver particles.
As the curing agent, a phenol curing agent and an imidazole curing agent can be used. The details are described below.

[Phenol hardener]
Specific examples of the phenol resin-based hardener include phenol novolac resins, cresol novolac resins, bisphenol novolac resins, phenol-biphenol novolac resins, and other novolac phenol resins; polyvinyl phenol; Multifunctional phenol resins such as triphenylmethane phenol resins; modified phenol resins such as terpene modified phenol resins and dicyclopentadiene modified phenol resins; Phenol aralkyl resins, naphthol aralkyl resins having a phenylene and / or biphenylene skeleton, and other phenol aralkyl phenol resins; bisphenol A, bisphenol F (dihydroxydiphenylmethane), etc. Bisphenol compounds; Compounds having a biphenyl group such as 4,4'-bisphenol. The phenol resin-based curing agent may include one or two or more kinds selected from the above specific examples.
As the phenol-based resin, in the specific examples described above, for example, a bisphenol compound is preferably used. As the bisphenol compound, for example, bisphenol F is preferably used. Thereby, an epoxy resin can be hardened and shrunk, and an appropriate silver particle connection structure can be formed.

[Imidazole-based hardener]
Specific examples of the imidazole-based hardener include 2-phenyl-1H-imidazole-4,5-dimethanol, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-methyl. Imidazole, 2-phenylimidazole, 2,4-diamine-6- [2-methylimidazolyl- (1)]-ethyl-s-three wells, 2-undecylimidazole, 2-seven Alkyl imidazole, 2,4-diamine-6- [2-methylimidazolyl- (1)]-ethyl-s-triisocyanuric acid adduct, 2-phenylimidazole isotrimerization Cyanate adduct, 2-methylimidazole isotrimeric cyanide adduct, 1,2,4-benzenetricarboxylic acid 1-cyanoethyl-2-phenylimidazolium, 1,2,4-benzene 1-cyanoethyl-2-undecylimidazolium tricarboxylic acid and the like. As the imidazole-based curing agent, one or a combination of two or more of the above specific examples can be used.

The lower limit of the content of the hardener in the paste-like adhesive composition is preferably 100 parts by mass based on 100 parts by mass of the total amount of the epoxy monomer and the epoxy resin in the paste-like adhesive composition. 1 part by mass or more, more preferably 1.5 parts by mass or more. Thereby, the paste-like adhesive composition can be appropriately hardened and shrunk to form an appropriate silver particle connection structure.
The upper limit of the content of the hardener in the paste-like adhesive composition is preferably 100 parts by mass based on 100 parts by mass of the total amount of the epoxy monomer and the epoxy resin in the paste-like adhesive composition. It is 10 parts by mass or less, and more preferably 5 parts by mass or less. Thereby, it is preferable from a viewpoint that a polymer component does not inhibit the formation of a silver particle connection structure.

(Hardening accelerator)
The slurry-like adhesive composition of this embodiment may contain, for example, a hardening accelerator that accelerates the reaction between an epoxy monomer or an epoxy resin and a hardener.
Specific examples of the hardening accelerator include phosphorus-containing atoms such as organic phosphines, tetra-substituted phosphonium compounds, phosphate betaine compounds, adducts of phosphine compounds and quinone compounds, adducts of phosphonium compounds and silane compounds, and the like. Compounds; fluorene or tertiary amines such as dicyandiamine, 1,8-diazylbicyclo [5.4.0] undecene-7, benzyldimethylamine; quaternary ammonium salts of the above hydrazone or the above tertiary amine A nitrogen atom-containing compound and the like. As the hardening accelerator, one or a combination of two or more of the above specific examples can be used.

(Low stress agent)
The slurry-like adhesive composition of this embodiment may contain, for example, a low-stress agent.
Specific examples of the low-stress agent include polysiloxane compounds such as polysiloxane oil and polysiloxane; polybutadiene compounds such as polybutadiene maleic anhydride adduct; and acrylonitrile butadiene copolymerization. Compounds etc. As the low-stress agent, one or a combination of two or more of the above specific examples can be used.

(Silane coupling agent)
In order to improve the adhesiveness between the slurry-like adhesive composition and the substrate, the slurry-like adhesive composition of the present embodiment may contain, for example, a silane coupling agent.
As the silane coupling agent, specifically, vinylsilane such as vinyltrimethoxysilane, vinyltriethoxysilane, and the like; 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3 -Glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxy Epoxy silanes such as methylpropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane; styrylsilanes such as p-styryltrimethoxysilane; 3-methylpropene Oxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryl Silyl methacrylates such as methoxypropyltriethoxysilane; acrylic silanes such as 3- (trimethoxysilane) propyl methacrylate and 3-propenyloxypropyltrimethoxysilane; N-2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethyl Oxysilane, 3-amino Aminosilanes such as propyltriethoxysilane, N- (1,3-dimethyl-butylene) propylamine 3-triethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane ; Isotricyanate silane; alkyl silane; urethane silane such as 3-uretopropyltrialkoxysilane; 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, etc. Mercaptosilane; isocyanate silane such as 3-isocyanatepropyltriethoxysilane. As the silane coupling agent, one or a combination of two or more of the above specific examples can be used.

(Manufacturing method of paste-like adhesive composition)
The manufacturing method of the slurry-form adhesive composition of this embodiment is demonstrated.
The method for producing a slurry-like adhesive composition includes a mixing step of mixing the raw material components to prepare a mixture, and a defoaming step of removing air contained in the mixture.

(Mixing step)
In the mixing step, the raw material components are mixed to prepare a mixture.
The method of mixing is not limited, and for example, a three-roll mill, a mixer, or the like can be used. Thereby, a raw material component is mixed and a mixture is obtained.

(Defoaming step)
The air contained in the mixture is removed in a defoaming step.
The method for removing the air contained in the mixture is not limited, and it can be performed by, for example, placing the mixture under a vacuum. Thereby, a slurry-like adhesive composition was obtained.

(Slurry-like adhesive composition)
As a hardening condition of the slurry-like adhesive composition of the present embodiment, for example, the temperature is raised from near room temperature (20 ° C to 30 ° C) to 100 ° C at a temperature increase rate of 0.5 ° C / min to 30 ° C / min. Above and 300 ° C or lower, and further heat-treated at a temperature after the temperature rise for 10 minutes or longer and 2 hours or shorter. Thereby, the paste-like adhesive composition can be sufficiently cured.

The paste-like adhesive composition of this embodiment was applied to a copper lead frame so that the coating thickness became 25 ± 10 μm, and then a bare silicon wafer having a length of 2 mm × width of 2 mm was placed on the paste-like adhesive. To obtain a laminated body, and then the laminated body was heated from a temperature of 25 ° C. to 175 ° C. in an atmospheric environment for 30 minutes, and further maintained at 175 ° C. for 30 minutes to obtain a hardened body, and measured at a temperature of 260 ° C. The lower limit of the shear strength between the hardened silicon and the copper circuit is, for example, preferably 5.0 MPa or more, more preferably 6.0 MPa or more, even more preferably 7.0 MPa or more, and even more preferably 7.5 MPa. The above is particularly preferably 8.0 MPa or more. Thereby, it is possible to improve reliability such as close contact reliability and mounting reliability of the paste-like adhesive composition. It is also preferable from the viewpoint of improving the shear strength of a metal such as a silver-plated lead frame, a Pre Plated Leadframe (hereinafter, also referred to as PPF), and a bare silicon wafer.
The upper limit of the shear strength may be, for example, 15.0 MPa or less, or may be 14.0 MPa or less.

(use)
The application of the slurry-like adhesive composition of this embodiment is demonstrated.
The paste-like adhesive composition of this embodiment can be in close contact with various adherends, and further has excellent heat dissipation properties. Specific examples of the adherend include semiconductor elements such as ICs and LSIs; substrates such as lead frames, BGA substrates, mounting substrates, and semiconductor wafers; and heat dissipation members such as heat sinks and heat sinks.
The semiconductor element may be a power plant, for example. In the present embodiment, the power device refers to, for example, a power consumption of 1.7 W or more.

The paste-like adhesive composition of this embodiment is preferably used in, for example, semiconductor devices such as semiconductor packages.
Among them, as types of semiconductor packages, specifically, MAP (Mold Array Package), QFP (Quad Flat Package), SOP (Small Small Package), CSP (Chip Size Package), QFN (Quad Flat Non-leaded Package), SON (Small Outline Non-leaded Package), BGA (Ball Gate Array; Ball Grid Array), LF-BGA (Lead Frame BGA; Lead Flame BGA), FCBGA (Flip Chip BGA), MAPBGA (Molded Array Process BGA), eWLB (Embedded Crystal Round BGA; Embedded Wafer-Level BGA), Fan-In eWLB, Fan-Out eWLB and other types.

Hereinafter, an example of a semiconductor device using the paste-like adhesive composition of the present embodiment will be described.
FIG. 1 is a cross-sectional view showing an example of a semiconductor device according to this embodiment.
The semiconductor device 100 according to this embodiment includes a substrate 30 and a semiconductor element 20 mounted on the substrate 30 through the adhesive layer 10 which is a cured product of the paste-like adhesive composition. That is, the adhesive layer 10 is obtained by hardening a paste-like adhesive composition.
The semiconductor element 20 and the base material 30 are electrically connected, for example, via a bonding wire 40 or the like. The semiconductor element 20 is sealed by, for example, a sealing resin 50.

The lower limit of the thickness of the adhesive layer 10 is, for example, preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 20 μm or more. Thereby, the heat capacity of the hardened | cured material of a slurry-form adhesive composition can be improved, and a heat radiation property can be improved.
The upper limit value of the thickness of the adhesive layer 10 may be, for example, 100 μm or less, or 50 μm or less.

In FIG. 1, the base material 30 is, for example, a lead frame. At this time, the semiconductor element 20 is mounted on the wafer pad 32 or the substrate 30 via the wafer adhesive layer 10. In addition, the semiconductor element 20 is electrically connected to the external lead 34 (the base material 30) via a bonding wire 40, for example. The lead frame, that is, the base material 30 is made of, for example, a 42 alloy or a Cu frame.

The substrate 30 may be an organic substrate or a ceramic substrate. As the organic substrate, for example, an epoxy resin, a cyanate resin, a maleimide resin, or the like is preferably used.
The surface of the substrate 30 may be coated with a metal such as silver or gold. Thereby, the adhesiveness of the adhesive layer 10 and the base material 30 can be improved.

FIG. 2 is a modification of FIG. 1 and is a cross-sectional view showing an example of a semiconductor device 100 according to this embodiment.
In the semiconductor device 100 according to this modification, the substrate 30 is, for example, an interposer. In the interposer, that is, the substrate 30, a plurality of solder balls 52 are formed on one surface on which the semiconductor element 20 is mounted and the other surface on the opposite side. At this time, the semiconductor device 100 is connected to another wiring substrate via a solder ball 52.

(Method for Manufacturing Semiconductor Device)
An example of a method for manufacturing a semiconductor device according to this embodiment will be described.
First, a paste-like adhesive composition is coated on the base material 30, and then the semiconductor element 20 is placed thereon. That is, the base material 30, the paste-like adhesive composition, and the semiconductor element 20 are laminated in this order. The method for applying the paste-like adhesive composition is not limited, and specifically, a spray method, a printing method, an inkjet method, or the like can be used.
Next, the paste-like adhesive composition is pre-cured and post-cured to make the paste-like adhesive composition a cured product. By heat treatment such as pre-hardening and post-hardening, a thermal conductive layer formed by aggregating the silver particles in the paste-like adhesive composition and disappearing the interfaces between the plurality of silver particles is formed in the adhesive layer 10. Thereby, the base material 30 and the semiconductor element 20 are bonded via the adhesive layer 10. 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. Thereby, a semiconductor device can be manufactured.

As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to the said embodiment, The structure can be changed within the range which does not change the meaning of this invention.
[Example]

Hereinafter, the present invention will be described in detail using examples, but the present invention is not limited in any way by these examples.

＜ Raw material ingredients ＞
First, the raw material components used in Examples and Comparative Examples will be described in detail.

(Main agent)
The following were used as the main agent.
・ Epoxy oligomer 1: Bisphenol-F-diglycidyl ether (manufactured by Nippon Kayaku Co., Ltd., RE-403S, Mw = 236, epoxy equivalent 165g / eq)
・ Epoxy oligomer 2: a mixture of m-glycidyl ether and p-glycidyl ether (manufactured by Sakamoto Yakuhin Kogyo Co., Ltd., m, p-CGE, Mw = 165, epoxy equivalent 165 g / eq)

(hardener)
The following were used as the hardener.
・ Phenol hardener 1: Dihydroxydiphenylmethane (DIC-BPF, manufactured by DIC Corporation)
・ Imidazole hardener 1: 2-phenyl-1H-imidazole-4,5-dimethanol (manufactured by SHIKOKU CHEMICALS CORPORATION, 2PHZ-PW)

(Hardening accelerator)
The following were used as hardening accelerators.
・ Hardening accelerator 1: Dicyandiamide (manufactured by ADEKA CORPORATION, EH-3636AS)

(monomer)
The following were used as monomers.
-Monofunctional acrylic monomer 1: 1, 4-cyclohexanedimethanol monoacrylate (manufactured by Nihon Kasei CO., LTD, CHDMMA)
・ Monofunctional acrylic monomer 2: 2-phenoxyethyl methacrylate (manufactured by KYOEISHA CHEMICAL Co., LTD., PO)

(Silver particles)
As the silver particles, those shown in Table 1 below were used.

[Table 1]

<Preparation of slurry-like adhesive composition>
The slurry-like adhesive composition of each Example and each comparative example was produced. As a manufacturing method, each raw material component of the compounding quantity shown in the following Table 2 was kneaded with a three-roll mill at normal temperature, and was produced.

＜ Evaluation ＞
The slurry-like adhesive composition of each example and each comparative example was evaluated by the following method.

(Shear strength)
The slurry-like adhesive composition of each Example and each comparative example evaluated the shear strength by the following method. Detailed description.
First, a copper lead frame (hereinafter, also referred to as copper LF) and a silicon wafer (length 2 mm × width 2 mm) were prepared. Next, the paste-like adhesive composition of each example and each comparative example was coated on a silicon wafer so that the coating thickness became 25 ± 10 μm, and a copper lead frame was placed thereon. That is, a laminated body in which a silicon wafer, a paste-like adhesive composition, and a copper lead frame were laminated in this order was produced. The surface of the copper lead frame that is in contact with the paste-like adhesive composition is made of copper.
Next, the temperature was raised from 25 ° C. to 175 ° C. for 30 minutes in an atmospheric environment, and then a heat treatment was performed at 175 ° C. for 30 minutes to harden the slurry-like adhesive composition of the laminate to be a cured product.
Next, the shear strength of the silicon wafer and the copper lead frame sandwiched with the hardened material was measured. As a measurement condition, measurement was performed at a temperature of 260 ° C for 20 seconds. The evaluation results are shown in Table 2 below as a result of the shear strength of Si-copper LF. The unit is MPa.
The results of the evaluation of the shear strength of the copper lead frame using a silver-plated lead frame on which the surface of the copper lead frame was silver-plated are shown in Table 2 below as a result of the shear strength of the Si-silver-plated LF. The surface of the silver-plated lead frame that is in contact with the paste-like adhesive composition is made of silver.
The results of evaluating the shear strength of a copper lead frame using a Pre Plated Leadframe (hereinafter also referred to as PPF) are shown in the following table as the result of the shear strength of Si-PPF. 2. PPF is plated with Ni, Pd, and Au in order on the copper lead frame. The surface of the PPF in contact with the paste-like adhesive composition is made of gold Au.

(Residual resin rate)
About the slurry-like adhesive composition of each Example and each comparative example, the resin residual rate was evaluated by the following method. The slurry-like adhesive composition of each example and each comparative example was subjected to thermogravimetric analysis (Thermogravimetry-Differetial Thermal Analysis: TG-DTA). As the conditions for thermogravimetric measurement, the following conditions were set: the temperature was increased from 30 ° C to 200 ° C at a temperature increase rate of 10 ° C / min in an atmospheric environment, followed by heat treatment at 200 ° C for 60 minutes, and then at 10 ° C / The temperature rising rate of the temperature was raised from a temperature of 200 ° C to 450 ° C, followed by a heat treatment at a temperature of 450 ° C for 10 minutes. In addition, the measurement is performed in an atmospheric environment.
100% of the weight reduction rate of the slurry-like adhesive composition after heat treatment at 200 ° C for 60 minutes relative to the slurry-like adhesive composition of each of the Examples and Comparative Examples before the temperature increase is W1 [%] .
In addition, 100% of the weight reduction rate of the slurry-like adhesive composition after heat-treating at 450 ° C for 10 minutes with respect to the slurry-like adhesive composition of each of the Examples and Comparative Examples before the temperature increase is W2 [ %].
Next, from the measured W1 and W2, (W2-W1) / W2 was calculated. The evaluation results are shown in Table 2 below.
In addition, W1 and W2 are positive values or zero values. For example, when the weight of the slurry-like adhesive composition after heat treatment at 200 ° C. for 60 minutes is 90% relative to the weight of the slurry-like adhesive composition before heating, the weight reduction rate is 10%.
Here, the temperature was raised from 30 ° C to 200 ° C at a temperature increase rate of 10 ° C / min, followed by heat treatment at 200 ° C for 60 minutes, and then the temperature was increased from 200 ° C to 450 ° C at a temperature increase rate of 10 ° C / min. Next, the behavior of the monomer and the main agent when heat-treated at a temperature of 450 ° C. for 10 minutes will be described.
First, the temperature was raised from 30 ° C. to 200 ° C. at a temperature increase rate of 10 ° C./minute, and then, when the heat treatment was performed at 200 ° C. for 60 minutes, components that did not cause a hardening reaction in the monomer and the main agent were volatilized. Moreover, the component which causes a hardening reaction hardens sufficiently.
Next, the temperature was raised from 200 ° C. to 450 ° C. at a temperature increase rate of 10 ° C./minute, and then heat treatment was performed at 450 ° C. for 10 minutes, thereby completely decomposing the components that did not cause a hardening reaction in the monomer and the main agent.
From the above, the molecular (W2-W1) represents the mass fraction of the hardened monomer and the main agent. The denominator W2 represents the sum of the mass fraction of the hardened monomer, the main component, and the mass fraction of the volatile monomer. Therefore, (W2-W1) / W2 represents the ratio of the monomer and the hardened monomer to the base agent and the base agent.

(Thermal cycle test)
The hardened | cured material of the slurry-form adhesive composition of each Example and each comparative example was heat-tested, and the adhesion reliability was evaluated. The detailed method is shown below.
First, a copper lead frame (hereinafter, also referred to as copper LF) and a silicon wafer (length 2 mm × width 2 mm, thickness 0.35 mm) were prepared. Next, the paste-like adhesive composition of each example and each comparative example was coated on a silicon wafer so that the coating thickness became 25 ± 10 μm, and a copper lead frame was placed thereon. That is, a laminated body in which a silicon wafer, a paste-like adhesive composition, and a copper lead frame were laminated in this order was produced. The surface of the copper lead frame that is in contact with the paste-like adhesive composition is made of copper.
Next, the temperature was raised from 25 ° C. to 175 ° C. for 30 minutes in an atmospheric environment, and then a heat treatment was performed at 175 ° C. for 60 minutes to harden the slurry-like adhesive composition of the laminate to produce a cured product.
Next, when the step of heat-treating the cured product at a temperature of 160 ° C. for 30 minutes and further at a temperature of 25 ° C. for 30 minutes was set as one cycle, a thermal cycle test was performed in which heat treatment was performed for 10 cycles. After the thermal cycle test, visually confirm whether peeling occurred between the silicon wafer and the hardened material of the paste-like adhesive composition, between the copper lead frame and the hardened material of the paste-like adhesive composition, and use the following criteria did an evaluation. The evaluation results are shown in Table 2 below as a result of the thermal cycle test of Si-copper LF.
(Circle): There is no peeling between a silicon wafer and a hardened | cured material, and there is no peeling between a copper lead frame and a hardened | cured material.
×: Peeling occurred between the silicon wafer and the cured product, or peeling occurred between the copper lead frame and the cured product.
Further, instead of the copper lead frame, a silver-plated lead frame and a PPF each having a silver-plated surface were used, and the adhesion to the adherend was evaluated in the same manner as the copper lead frame. The evaluation results are shown in Table 2 below as the results of thermal cycle tests of Si-silver-plated LF and Si-PPF, respectively.

(Chip-Chip thermal diffusion coefficient)
The slurry-type adhesive composition of each Example and each comparative example evaluated the Chip-Chip thermal diffusion coefficient by the following method. This is explained in detail below.
First, two silicon wafers having a length of 10 mm × a width of 10 mm × a thickness of 350 μm were prepared. A paste-like adhesive composition was applied to one silicon wafer so that it was 25 ± 10 μm, and another silicon wafer was laminated thereon. That is, a laminated body in which a silicon wafer, a paste-like adhesive composition, and a silicon wafer were laminated in this order was produced.
Next, after raising the temperature from 25 ° C. to 175 ° C. over 30 minutes, heat treatment was performed at a temperature of 175 ° C. for 60 minutes to thereby harden the slurry-like adhesive composition of the laminate to be a cured product. Thus, a test piece in which a cured product of the slurry-like adhesive composition was sandwiched by two silicon wafers was produced.
Next, with respect to the test piece, a laser flash method was used to measure the thermal diffusion coefficient in the thickness direction of the test piece, and this was used as the evaluation result of the Chip-Chip thermal diffusion coefficient. The measurement temperature of the thermal diffusion coefficient was set to 25 ° C. The evaluation results are shown as the results of the Chip-Chip thermal diffusion coefficient of Si-Si in Table 2 below. The unit is cm ² / sec. Here, the higher the value of the Chip-Chip thermal diffusion coefficient, the better the evaluation result.
In addition, instead of the silicon wafer, a gold-plated silicon wafer coated with Ti, Ni, and Au in this order was used for a silicon wafer having a length of 10 mm × width of 10 mm × thickness of 350 μm, and the Chip-Chip thermal diffusion coefficient was measured. Here, when a laminated body is produced, it laminates so that a slurry-like adhesive composition may contact the surface which consists of Au. The evaluation results are shown in Table 2 below as the results of the Chip-Chip thermal diffusion coefficient of Au-Au.
When a sintered paste-like adhesive composition is used, the gold-plated silicon wafer is a favorable evaluation of the sintered paste-like adhesive composition from the point that the interface between the gold plating layer and the paste-like adhesive composition can be eliminated. method.

(Observation of the connection structure of silver particles)
A scanning electron microscope (Scanning Electron Microscope: SEM) was used to observe the cross section of the semiconductor device using the paste-like adhesive composition of each of the Examples and Comparative Examples, and it was confirmed whether or not a silver particle connection structure was formed. The detailed method is shown below.
First, a copper lead frame (hereinafter, also referred to as copper LF) and a silicon wafer (length 2 mm × width 2 mm, thickness 0.35 mm) were prepared. Next, the paste-like adhesive composition of each example and each comparative example was coated on a silicon wafer so that the coating thickness became 25 ± 10 μm, and a copper lead frame was placed thereon. That is, a laminated body in which a silicon wafer, a paste-like adhesive composition, and a copper lead frame were laminated in this order was produced. The surface of the copper lead frame that is in contact with the paste-like adhesive composition is made of copper.
Next, the temperature was raised from 25 ° C. to 175 ° C. for 30 minutes in an atmospheric environment, and then a heat treatment was performed at 175 ° C. for 60 minutes to harden the slurry-like adhesive composition of the laminate to produce a cured product.
Next, the cross section of the hardened | cured material was observed by SEM. The evaluation results are shown in Table 2 below for those having a silver particle connection structure formed as "○" and those not formed. The SEM observation results of Example 1 and Comparative Example 3 are shown in FIG. 3 and FIG. 4, respectively.

(Construction reliability)
The semiconductor devices using the paste-like adhesive composition of each example and each comparative example were evaluated for the reliability of assembly. As an evaluation of the reliability of the assembly, the MSL (Moisture Sensitivity Level) performance was measured. MSL performance was implemented as MSL Lv2a in accordance with JEDEC STANDARD 22-A113D. The detailed method is shown below.
First, a copper lead frame (hereinafter, also referred to as copper LF) and a silicon wafer (length 2 mm × width 2 mm, thickness 0.35 mm) were prepared. Next, the paste-like adhesive composition of each example and each comparative example was coated on a silicon wafer so that the coating thickness became 25 ± 10 μm, and a copper lead frame was placed thereon. That is, a laminated body in which a silicon wafer, a paste-like adhesive composition, and a copper lead frame were laminated in this order was produced. The surface of the copper lead frame that is in contact with the paste-like adhesive composition is made of copper.
Next, after raising the temperature from 25 ° C. to 175 ° C. for 30 minutes in the atmospheric environment, heat treatment was performed at a temperature of 175 ° C. for 60 minutes to harden the slurry-like adhesive composition of the laminate to be a cured product.
Next, the hardened body was sealed with an epoxy resin composition for semiconductor sealing (manufactured by Sumitomo Bakelite Company Limited, EME-G700LS) so that the package size became 17.9 mm × 7.2 × 2.5 mm in thickness, and the semiconductor seal was cured at a temperature of 175 ° C An epoxy resin composition was used for 4 hours, thereby obtaining a semiconductor device.
After the semiconductor device was subjected to a moisture absorption treatment for 120 hours under the conditions of 60 ° C and a relative humidity of 60%, IR reflow treatment was performed (three times under the conditions of 260 ° C and 10 seconds). Next, the semiconductor device after the IR reflow process was evaluated for the presence or absence of peeling at the interface between the lead frame and the silicon wafer using a transmission-type ultrasonic flaw detection device. Eight semiconductor devices were evaluated, and the average value was evaluated using the following criteria. The evaluation results are shown in Table 2 below as a result of the structural reliability of Si-copper LF.
○: About the interface between the copper lead frame and the cured product of the paste-like adhesive composition, the interface between the cured product of the paste-like adhesive composition and the silicon wafer, and the cured product of the wafer and the semiconductor sealing epoxy resin composition Interface, the area of the interface where peeling occurs is less than 20% of the area of 2mm × 2mm.
×: The interface between the copper lead frame and the cured product of the paste-like adhesive composition, the interface between the cured product of the paste-like adhesive composition and the silicon wafer, and the curing of the silicon wafer and the epoxy resin composition for semiconductor sealing The area of the interface of the object is 20% or more with respect to the area of 2 mm × 2 mm.
Further, instead of the copper lead frame, a silver-plated lead frame and a PPF each having a silver-plated surface were used, and the mounting reliability was evaluated in the same manner as the copper lead frame. The evaluation results are shown in Table 2 below as the results of the structural reliability of Si-silver-plated LF and Si-PPF, respectively.

[Table 2]

As shown in Table 2, it was confirmed that the slurry-like adhesive composition of each example exhibits a balance of reliability, such as mounting reliability and adhesion reliability, compared with the slurry-like adhesive composition of each comparative example. Chip-Chip thermal diffusion coefficient and other heat dissipation properties.

In addition, Comparative Example 1 is a sintered paste-like adhesive composition.
In addition, Comparative Example 2 is a mixed-type and sintered type slurry-type adhesive composition. However, in Comparative Example 2, the shape of the silver particles was only spherical and the silver particles were excessively attracted to each other. From this, it is considered that the interface between the cured product of the paste-like adhesive composition of Comparative Example 2 and the adherend is destroyed by the shrinkage of the silver particles. Therefore, the paste-like adhesive composition of Comparative Example 2 is considered to be a semiconductor device having poor reliability.
In addition, Comparative Example 3 is an adhesive-type paste-like adhesive composition. Conventional adhesives have excellent adhesion to the adherend, and have excellent reliability of semiconductor devices. However, compared with the paste-like adhesive composition of the Example, the paste-like adhesive composition of the comparative example 3 is a thing which is inferior in reliability of a semiconductor device. In order to confirm this reason, the cross section of the hardened | cured material of the laminated body of the comparative example 3 produced in the said thermal-cycle test was observed with the scanning microscope. As a result, it was confirmed that the hardened material of the laminated body of Comparative Example 3 had almost no silver particles near the interface with the adherend, and the silver particles were concentrated near the center in the thickness direction of the hardened material of the paste-like adhesive composition. This is presumably due to the shape of the silver particles and the particle size distribution of the silver particles. In addition, the conventional paste-like adhesive composition is one in which silver particles are uniformly dispersed. Thereby, it was observed that the hardened | cured material of the slurry-like adhesive composition of the comparative example 3 received the internal stress by shrinkage of the silver particle at the interface with an adherend, and the interface was destroyed.

This application claims the priority of Japanese Patent Application No. 2017-232247 filed on December 4, 2017, the entire contents of which are incorporated herein.

no

FIG. 1 is a cross-sectional view showing an example of a semiconductor device according to this embodiment.

FIG. 2 is a cross-sectional view showing an example of a semiconductor device according to this embodiment.

3 is a result of cross-sectional observation of a semiconductor device using the paste-like adhesive composition of Example 1 using a scanning electron microscope.

FIG. 4 is a result of cross-sectional observation of a semiconductor device using the paste-like adhesive composition of Comparative Example 3 using a scanning electron microscope.

Claims (9)

A paste-like adhesive composition containing: Epoxy resin; and Silver particles, and A silver particle connection structure in which a plurality of the above-mentioned silver particles' interfaces are eliminated by heat treatment, This paste-like adhesive composition was coated on a copper lead frame so that the coating thickness became 25 ± 10 μm, and then a bare silicon wafer having a length of 2 mm × width of 2 mm was placed on the paste-like adhesive composition. The laminated body was obtained, and then the laminated body was heated from the temperature of 25 ° C. to 175 ° C. for 30 minutes in the atmospheric environment, and further maintained at 175 ° C. for 30 minutes to obtain a hardened body. The shear strength between the bare silicon of the hardened body and the copper lead frame is 5.0 MPa to 15.0 MPa. The paste-like adhesive composition according to claim 1, wherein: The silver particles include scaly silver particles. The paste-like adhesive composition according to claim 2, wherein: The silver particles also include spherical silver particles. The paste-like adhesive composition according to claim 3, wherein The content of the scaly silver particles in the silver particles is 5 parts by mass or more and 60 parts by mass or less with respect to the total amount of the scaly silver particles and the spherical silver particles. The paste-like adhesive composition according to claim 1, wherein: The content of the silver particles is 50 parts by mass or more and 90 parts by mass or less with respect to the entire paste-like adhesive composition. The paste-like adhesive composition according to claim 1, wherein: The epoxy resin includes an epoxy oligomer or an epoxy polymer. The paste-like adhesive composition according to claim 1, further comprising a hardener. A semiconductor device includes: Substrate; and The semiconductor element mounted on the substrate through an adhesive layer, The said adhesive layer consists of hardened | cured material of the slurry-form adhesive composition as described in any one of Claims 1-7. The semiconductor device according to claim 8, wherein: The base material is one selected from the group consisting of a lead frame, a BGA substrate, a mounting substrate, a semiconductor wafer, a heat spreader, and a heat sink.