TW201602220A - Resin composition for encapsulation and semiconductor device - Google Patents

Abstract

Provided is a resin composition for sealing, used to seal a semiconductor element and a bonding wire which is connected to the semiconductor element and which has copper as a primary component, wherein the resin composition comprises an epoxy resin, a curing agent, and a sulfur-containing compound and has the swelling rate (S), as calculated under specific conditions, of 150% or less.

Description

Sealing resin composition, and semiconductor device

The present invention relates to a resin composition for sealing and a semiconductor device.

In order to improve the reliability of a semiconductor device including a bonding wire, various studies have been made on a resin composition for sealing. As such a technique, for example, those described in Patent Document 1 can be cited.

Patent Document 1 describes an epoxy resin composition for semiconductor encapsulation containing a biphenyl type epoxy resin having a hydrolyzable chlorine content of 10 to 20 ppm.

Prior technical literature

Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2013-67694

Regarding the use of a cured resin composition for sealing a semiconductor element, and a connection A semiconductor device in which a semiconductor element is sealed by a bonding wire containing Cu as a main component is required to improve reliability.

According to the invention, there is provided a resin composition for sealing which is used for sealing a semiconductor element and a bonding wire which is connected to the semiconductor element and has Cu as a main component, and the resin composition for sealing contains an epoxy resin and hardens The swelling ratio S calculated by the following conditions 1 is 150% or less, and the condition is as follows: (Condition 1: The sealing resin composition is thermally cured at 175 ° C for 4 hours, and obtained. The cured product is pulverized to obtain a pulverized material, and then 1.0 g of the pulverized material and a structure composed of a lead frame and a semiconductor wafer which are connected to each other via a Cu wire (maximum diameter D ₀ = 20 μm at a center point), The Cu wire is placed in a closed container in such a manner that the Cu wire is exposed to air, and heat treatment is performed under an air atmosphere at 200 ° C for 96 hours. Then, the maximum diameter D ₁ of the center point of the Cu wire is measured. As a result of the calculation, the expansion ratio S = D ₁ / D ₀ × 100 (%) was calculated.

Moreover, according to the present invention, there is provided a semiconductor device comprising: a semiconductor element; a bonding wire connected to the semiconductor element and containing Cu as a main component; and a sealing resin composed of a cured product of the sealing resin composition, And the above semi-guide The body member is sealed to the above bonding wire.

According to the present invention, the reliability of the semiconductor device can be improved.

10‧‧‧ die adhesion material

20‧‧‧Semiconductor components

22‧‧‧electrode pads

30‧‧‧Substrate

32‧‧‧ die holder

34‧‧‧External leads

40‧‧‧bonding line

50‧‧‧ sealing resin

60‧‧‧structure

62‧‧‧Cu line

64‧‧‧ lead frame

66‧‧‧Semiconductor wafer

70‧‧‧Contained containers

80‧‧‧Smashed

90‧‧‧Kapton tape

100‧‧‧Semiconductor device

The above and other objects, features and advantages of the present invention will become more apparent from

Fig. 1 is a cross-sectional view showing the semiconductor device of the embodiment.

Fig. 2 is a cross-sectional view for explaining a method of measuring the expansion ratio.

Hereinafter, embodiments will be described using the drawings. In the drawings, the same components are denoted by the same reference numerals, and the description is omitted as appropriate.

Fig. 1 is a cross-sectional view showing a semiconductor device 100 of the present embodiment.

The sealing resin composition of the present embodiment is for sealing a semiconductor element and a bonding wire which is connected to the semiconductor element and has Cu as a main component, and the sealing resin composition contains an epoxy resin, a curing agent, and Sulfur-containing compounds. Further, the expansion ratio S of the resin composition for sealing calculated under the following condition 1 was 150% or less.

(Condition 1: The sealing resin composition was thermally cured at 175 ° C for 4 hours, and the obtained cured product was pulverized to obtain a pulverized product; then, 1.0 g of the pulverized material and the pulverized material were passed through Cu a wire frame (maximum diameter D _{0 of the} center point D ₀ = 20 μm) and a structure composed of a lead frame and a semiconductor wafer connected to each other, and the Cu wire is placed in a sealed container so as to be exposed to air in an air atmosphere at 200 ° C The heat treatment is performed under conditions of 96 hours; then, the maximum diameter D ₁ of the center point of the Cu line is measured, and the expansion ratio S = D ₁ / D ₀ × 100 (%) is calculated from the obtained result)

One of the indexes indicating the reliability of the semiconductor device is high temperature storage characteristics. The high-temperature storage characteristics can be evaluated, for example, based on the connectivity of the connection portion of the bonding wire and the semiconductor element having Cu as a main component after long-term storage under high temperature conditions. The present inventors have newly found that by controlling the expansion ratio S measured under the above condition 1, it is possible to improve the high-temperature storage characteristics. In the present embodiment, based on such a finding, the sealing resin composition having the expansion ratio S measured under the above condition 1 is 150% or less. Thereby, the high-temperature storage characteristics of the semiconductor device manufactured using the resin composition for sealing can be improved. Therefore, the reliability of the semiconductor device can be improved.

In the following, the semiconductor device 100 including the sealing resin composition of the present embodiment and the sealing resin 50 including the cured product of the sealing resin composition will be described in detail.

First, the resin composition for sealing will be described. The resin composition for sealing is used to seal a semiconductor element and a bonding wire connected to the semiconductor element and having Cu as a main component. In the present embodiment, a semiconductor package is formed by sealing a semiconductor element and a bonding wire with a sealing resin composed of a cured product of a sealing resin composition.

The semiconductor element is mounted, for example, on a substrate such as a die pad or an organic substrate constituting the lead frame or another semiconductor element. At this time, the semiconductor element is electrically connected to a lead wire, an organic substrate, or another semiconductor element constituting the lead frame via a bonding wire. The bonding wire is connected, for example, to an electrode pad provided on the semiconductor element. Regarding the electrode pad of the semiconductor element, for example, at least the surface is made of a metal material containing Al as a main component.

The bonding wire is composed of a metal material containing Cu as a main component. Examples of such a metal material include a metal material composed of a simple substance of Cu or an alloy material containing Cu as a main component and containing another metal.

In the present embodiment, a case where a bonding wire made of a metal material having a Cu content of 99.9% by mass or more is used as an example of a preferable aspect is used. In general, when such a Cu wire is used, there is a concern that it is difficult to improve the high-temperature storage characteristics of the semiconductor device. However, according to the present embodiment, by controlling the expansion ratio S described below, excellent high-temperature storage characteristics can be realized even when the Cu wire as described above is used.

The expansion ratio S of the resin composition for sealing calculated under the following condition 1 was 150% or less. Thereby, the high-temperature storage characteristics of the semiconductor device can be improved as described above.

Condition 1: The sealing resin composition was thermally cured at 175 ° C for 4 hours, and the obtained cured product was pulverized to obtain a pulverized product. Then, 1.0 g of the pulverized material and a structure composed of a lead frame and a semiconductor wafer which are connected to each other via a Cu wire (the maximum diameter of the center point D ₀ = 20 μm) are placed so that the Cu wire is exposed to the air. The mixture was placed in a closed container and heat-treated under an air atmosphere at 200 ° C for 96 hours. Then, the maximum diameter D ₁ of the center point of the Cu line was measured, and the obtained expansion ratio S = D ₁ / D ₀ × 100 (%) was calculated from the obtained result.

The pulverization treatment of the cured product of the above condition 1 can be carried out, for example, by using TI-100 (manufactured by CMT), and placing 5 g of the cured product into a pulverization vessel and pulverizing for 2 minutes. As the sealed container, for example, a glass petri dish having an inner diameter of 50 mm and a height of 17 mm can be used. The heat treatment is performed, for example, in a state where the entire Cu wire is exposed to the air. As the Cu wire, for example, a wire having a 4N grade, that is, a content of Cu of 99.99% by mass or more can be used.

Further, the center point of the Cu line is a point at which the distance from the one end of the lead frame is equal to the distance from the other end of the contact with the semiconductor wafer. Further, D ₀ and D ₁ each include a center point and a maximum diameter on a cross section perpendicular to the extending direction of the Cu line. When the cross section is an ellipse, the long diameter becomes the largest diameter, and in the case of a perfect circle, the diameter becomes the largest diameter.

In the semiconductor device including the sealing resin formed using the photosensitive resin composition containing a sulfur compound, it is difficult to obtain excellent high-temperature storage characteristics. It is envisaged that one of the factors is caused by prolonged exposure to a gas generated by a sulfur compound in a high temperature environment, thereby causing a decrease in connectivity between the Cu wire and the electrode pad. Therefore, although it is required to improve the high-temperature storage characteristics, it has not been sufficient as an index of the sealing resin composition which can maintain the connection reliability at the time of high-temperature storage, for example, for 1000 hours.

The present inventors have newly found that the expansion ratio S calculated under the above condition 1 can be an index indicating that the connection reliability at the time of high-temperature storage for a long period of time can be improved. The sealing resin composition of the present embodiment is based on such a finding, and the expansion ratio S calculated under the above condition 1 is controlled to 150% or less. Therefore, according to the sealing resin composition of the present embodiment, a semiconductor device excellent in high-temperature storage characteristics can be realized.

The expansion ratio S of the sealing resin composition is more preferably 145% or less from the viewpoint of improving the high-temperature storage characteristics of the semiconductor device. Further, the lower limit of the expansion ratio S is not particularly limited, and may be, for example, 101%.

In the present embodiment, the expansion ratio S of the resin composition for sealing can be controlled, for example, by appropriately adjusting the type or content of each component contained in the resin composition for sealing, the method of preparing the resin composition for sealing, and the like. As an example of the preparation method of the resin composition for sealing, the following surface treatment of the filler (D) by the sulfur-containing compound (C) is mentioned.

The resin composition for sealing contains an epoxy resin (A), a curing agent (B), and a sulfur-containing compound (C). Thereby, a sealing resin for sealing the bonding wires and the semiconductor elements can be formed by using the sealing resin composition.

((A) epoxy resin)

The epoxy resin (A) can be used for all monomers, oligomers, and polymers having two or more epoxy groups in one molecule, and the molecular weight or molecular structure thereof is not particularly limited.

In the present embodiment, the epoxy resin (A) may contain, for example, one or more selected from the group consisting of a biphenyl type epoxy resin, a bisphenol A type epoxy resin, and a bisphenol F type epoxy resin. Bisphenol type epoxy resin such as tetramethyl bisphenol F type epoxy resin; bismuth type epoxy resin; novolac type epoxy resin such as phenol novolac type epoxy resin, cresol novolak type epoxy resin; triphenol a polyfunctional epoxy resin such as a methane type epoxy resin or an alkyl modified trisphenol methane type epoxy resin; a phenol aralkyl type epoxy resin having a phenyl group skeleton; and a phenol aralkyl group having a phenyl group extending. An aralkyl type epoxy resin such as an epoxy resin; a dihydroxy naphthalene type epoxy resin; a naphthol type epoxy resin obtained by glycidyl etherification of a dihydroxy naphthalene dimer; Triglyceride uric acid, monoallyl diglycidyl isocyanurate, etc. Nuclear epoxy resin; dicyclopentadiene modified phenolic epoxy resin and other bridged cyclic hydrocarbon compounds modified phenolic epoxy resin. Among these, it is more preferable to contain at least one of an aralkyl type epoxy resin and a biphenyl type epoxy resin, and it is especially preferable to contain an aralkyl type epoxy resin. Further, a bisphenol type epoxy ring such as an aralkyl type epoxy resin, a biphenyl type epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, and a tetramethyl bisphenol F type epoxy resin The oxygen resin and the fluorene type epoxy resin preferably have crystallinity.

More preferably, the epoxy resin (A) is an epoxy resin represented by the following formula (1), an epoxy resin represented by the following formula (2), and the following formula (3). At least one of the group consisting of epoxy resins. In particular, it is preferable to use at least one of an epoxy resin represented by the following formula (1) and an epoxy resin represented by the following formula (2).

(In the formula (1), Ar ¹ represents a phenyl or anthracene group, and in the case where Ar ¹ is a naphthyl group, the glycidyl ether group may be bonded to any of the α-position and the β-position. Ar ² It represents any one of a phenyl group, a phenylene group or a naphthyl group. R _a and R _b each independently represent a hydrocarbon group having 1 to 10 carbon atoms. g is an integer of 0 to 5, and h is 0 to 8 Integer. n ³ represents the degree of polymerization, and the average value is 1~3)

(In the formula (2), a plurality of R _c each independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. n ⁵ represents a degree of polymerization, and the average value thereof is 0 to 4)

(In the formula (3), a plurality of R _d and R _e each independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. n ⁶ represents a degree of polymerization, and the average value thereof is 0 to 4)

The content of the epoxy resin (A) in the resin composition for sealing is preferably 1% by mass or more, more preferably 2% by mass or more, and particularly preferably 5% by mass or more, based on the entire resin composition for sealing. When the content of the epoxy resin (A) is at least the above lower limit value, it is possible to suppress breakage of the bonding wire due to an increase in viscosity of the resin composition for sealing. On the other hand, the content of the epoxy resin (A) in the resin composition for sealing is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 20% by mass based on the entire resin composition for sealing. %the following. When the content of the epoxy resin (A) is at most the above upper limit value, the moisture resistance reliability or the reflow resistance of the semiconductor device can be improved.

((B) hardener)

The curing agent (B) contained in the resin composition for sealing can be roughly classified into three types of an addition polymerization type hardener, a catalyst type hardener, and a condensation type hardener.

Examples of the addition polymerization type hardener used for the hardener (B) include, for example, diethylethylamine (DETA), triethylamine (TETA), and m-xylenediamine (MXDA). In addition to aromatic polyamines such as aliphatic polyamines, diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenyl hydrazine (DDS), dicyandiamide (DICY) is also included. a polyamine compound such as an organic acid diterpene; an alicyclic acid anhydride such as hexahydrophthalic anhydride (HHPA) or methyltetrahydrophthalic anhydride (MTHPA), trimellitic anhydride (TMA), An anhydride such as an aromatic acid anhydride such as pyromellitic dianhydride (PMDA) or benzophenone tetracarboxylic dianhydride (BTDA); a phenol resin curing agent such as a novolac type phenol resin or a poly(vinylphenol); a polythiol compound such as a thioester or a thioether; an isocyanate compound such as an isocyanate prepolymer or a blocked isocyanate; An organic acid such as a carboxylic acid-containing polyester resin.

Examples of the catalyst-type hardener used for the curing agent (B) include dimethylbenzylamine (BDMA) and 2,4,6-tris-dimethylaminomethylphenol (DMP-30). An amine compound; an imidazole compound such as 2-methylimidazole or 2-ethyl-4-methylimidazole (EMI24); a Lewis acid such as a BF3 complex or the like.

Examples of the condensation type hardener used for the curing agent (B) include a resol type phenol resin; a urea resin such as a methylol group-containing urea resin; and a melamine resin such as a hydroxymethyl group-containing melamine resin. Wait.

Among these, a phenol resin-based curing agent is preferred from the viewpoint of improving the balance between flame resistance, moisture resistance, electrical properties, curability, and storage stability. The phenol resin-based curing agent can be used for all monomers, oligomers, and polymers having two or more phenolic hydroxyl groups in one molecule, and the molecular weight and molecular structure thereof are not particularly limited.

The phenol resin-based curing agent used as the curing agent (B) may, for example, be one or more selected from the group consisting of a phenol novolak resin, a cresol novolak resin, and a novolac type varnish; Poly(vinylphenol); polyfunctional phenolic resin such as trisphenol methane phenol resin; modified phenolic resin such as terpene modified phenol resin or dicyclopentadiene modified phenol resin; having a phenylene skeleton and/or a phenol aralkyl resin having a biphenyl skeleton, an aralkyl resin such as a naphthol aralkyl resin having a phenyl group and/or a phenyl group extending; a bisphenol compound such as bisphenol A or bisphenol F; .

The curing agent (B) is preferably at least one curing agent containing a group selected from the group consisting of compounds represented by the following formula (4).

(In the formula (4), Ar ³ represents a phenyl or anthracene group, and in the case where Ar ³ is a naphthyl group, the hydroxyl group may be bonded to any of the α-position and the β-position. Ar ⁴ represents a benzene extension. Any one of a group, a biphenyl group or a naphthyl group. R ^f and R ^g each independently represent a hydrocarbon group having 1 to 10 carbon atoms, i represents an integer of 0 to 5, and j represents an integer of 0 to 8. ⁴ indicates the degree of polymerization, and the average value is 1 to 3)

The content of the curing agent (B) in the resin composition for sealing is preferably 2% by mass or more, more preferably 3% by mass or more, and particularly preferably 4% by mass or more based on the entire resin composition for sealing. When the content of the curing agent (B) is at least the above lower limit value, a resin composition for sealing having sufficient fluidity can be obtained, and the moldability can be improved. On the other hand, the content of the curing agent (B) in the resin composition for sealing is preferably 15% by mass or less, more preferably 13% by mass or less, and particularly preferably 11% by mass based on the entire resin composition for sealing. the following. By setting the content of the curing agent (B) to be equal to or lower than the above upper limit value, the moisture resistance reliability or the reflow resistance of the semiconductor device can be improved.

((C) sulfur-containing compounds)

The sulfur-containing compound (C) is a compound containing one or two or more sulfur atoms. By including the sulfur-containing compound (C) in the resin composition for sealing, the adhesion of the sealing resin formed using the resin composition for sealing to other members can be improved. Examples of other members include a substrate such as a lead frame, a bonding wire, and the like. Moreover, it is also possible to contribute to an improvement in the reflow resistance of the semiconductor device. Further, even when the sulfur-containing compound (C) is used as described above, excellent expansion rate S can be achieved by controlling the expansion ratio S calculated under the above condition 1. Therefore, according to This embodiment can be realized while achieving high-temperature storage characteristics and reflow resistance.

In the case where the sealing resin composition contains the following filler (D), for example, the filler (D) surface-treated with the sulfur-containing compound (C) can be put into the mixture together with the components other than the components. The machine is mixed to contain the sulfur-containing compound (C) in the resin composition for sealing. Further, the sulfur-containing compound (C) may be contained in the sealing resin composition by subjecting the filler (D) to the surface treatment described above, or may be contained in the mixer and mixed with other components. Inside the resin composition for sealing.

The sulfur-containing compound (C) may, for example, comprise one or more selected from the group consisting of a trialkoxymercaptodecane such as γ-mercaptopropyltrimethoxydecane or a γ-mercaptopropylmethyldimethoxy group. a decyl decane, such as a monoalkyl dialkoxynonyl decane such as decane or a dialkyl monoalkoxy decyl oxane such as γ-mercaptopropyl dimethyl methoxy decane, and 3-amino-1,2 , 4-triazole-5-thiol, 3,5-dimercapto-1,2,4-triazole, 3-hydroxy-1,2,4-triazole-5-thiol, 5-mercapto-1 A thiotriazole compound such as 2,4-triazole-3-methanol or the like which is represented by a 1,2,4-triazole ring or a 1,2,3-triazole ring having a sulfur-containing substituent. Among these, from the viewpoint of improving the adhesion of the sealing resin, it is more preferable to contain decyl decane, and particularly preferably γ-mercaptopropyltrialkoxy decane.

The content of the sulfur-containing compound (C) in the resin composition for sealing is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.15% by mass or more based on the entire resin composition for sealing. When the content of the sulfur-containing compound (C) is at least the above lower limit value, the adhesion of the sealing resin can be more effectively improved. Further, when the resin composition for sealing contains the filler (D), the dispersibility of the filler (D) in the resin composition for sealing can be improved. Therefore, moisture resistance reliability, reflow resistance, and the like can be more effectively improved. on the other hand, The content of the sulfur-containing compound (C) in the resin composition for sealing is preferably 2% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less based on the total amount of the resin composition for sealing. When the content of the sulfur-containing compound (C) is at most the above upper limit value, the fluidity of the sealing resin composition can be improved, and the moldability can be improved.

((D) filler material)

The resin composition for sealing may contain, for example, a filler (D). As the filler (D), those generally used for the epoxy resin composition for semiconductor sealing can be used, and examples thereof include molten spherical cerium oxide, melt-crushed cerium oxide, crystalline cerium oxide, talc, and alumina. Inorganic filler materials such as titanium dioxide and tantalum nitride; organic filler materials such as organic polyfluorene oxide powder and polyethylene powder. Among these, it is particularly preferable to use molten spherical cerium oxide. These filler materials may be used alone or in combination of two or more.

Further, the shape of the filler (D) is not particularly limited, and from the viewpoint of suppressing an increase in the melt viscosity of the resin composition for sealing and increasing the content of the filler, it is preferably spherical and granular as much as possible. Wide distribution.

In the present embodiment, the filler (D) previously subjected to the surface treatment using the sulfur-containing compound (C) can be mixed with the components other than the components and mixed into a mixer to prepare a resin composition for sealing.

The surface treatment of the filler (D) with the sulfur-containing compound (C) can be carried out, for example, as follows. First, after the filler (D) is charged into the mixer, stirring is started, and the sulfur-containing compound (C) is further added thereto, and the mixture is stirred for 1 to 5 minutes to obtain a filler (D) and a sulfur-containing compound (C). a mixture. The mixture was then removed from the mixer and placed. The placement time can be appropriately selected, and for example, it can be set to 3 minutes to 1 hour. Thereby, the table can be obtained by the sulfur-containing compound (C) Surface treatment filler (D). Further, the treated filler (D) is further subjected to heat treatment. The heat treatment can be carried out, for example, at 30 to 80 ° C for 0.1 to 10 hours. Further, in the present embodiment, the filler (D) may be obtained by spraying the filler (D) in the mixer with a sulfur-containing compound (C) by using a sprayer to obtain a filler (D). a mixture of sulfur-containing compounds (C). As the nebulizer, for example, a device that can spray fine droplets such as a two-fluid nozzle can be used. By using such a sprayer, it is preferred that the surface of the filler (D) is more uniformly treated with the sulfur-containing compound (C). In the present embodiment, the expansion ratio S can be controlled, for example, by adjusting the conditions of the surface treatment described above. Examples of the conditions of the surface treatment include the presence or absence of a sprayer, the standing time, the presence or absence of heat treatment, and heat treatment conditions.

Further, the above surface treatment of the filler (D) may not be performed.

The content of the filler (D) in the resin composition for sealing is preferably 35 mass% or more, more preferably 50 mass% or more, and still more preferably 65 mass% or more, based on the entire resin composition for sealing. When the content of the filler (D) is at least the above lower limit value, the low moisture absorption property and the low thermal expansion property can be improved, and the moisture resistance reliability or the reflow resistance can be more effectively improved. On the other hand, the content of the filler (D) in the resin composition for sealing is preferably 95% by mass or less, more preferably 93% by mass or less, and particularly preferably 90% by mass based on the entire resin composition for sealing. the following. By setting the content of the filler (D) to be equal to or less than the above upper limit, it is possible to suppress a decrease in moldability due to a decrease in fluidity of the resin composition for sealing, or a flow of a bonding wire due to high viscosity.

((E) ion trapping agent)

The resin composition for sealing may contain, for example, an ion scavenger (E). Thereby, the high-temperature storage characteristics of the semiconductor device including the sealing resin formed using the sealing resin composition can be more effectively improved. The ion scavenger (E) is not particularly limited and may, for example, be selected from the group consisting of hydrotalcites and multivalent gold. It is one type or two or more types of inorganic ion exchangers, such as an acid salt. Among these, it is particularly preferable to include hydrotalcites from the viewpoint of improving high-temperature storage characteristics.

The content of the ion scavenger (E) in the resin composition for sealing is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and particularly preferably 0.15% by mass or more based on the entire resin composition for sealing. When the content of the ion scavenger (E) is at least the above lower limit value, the high temperature storage characteristics can be more effectively improved. On the other hand, the content of the ion scavenger (E) in the resin composition for sealing is preferably, for example, 1% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass based on the entire resin composition for sealing. %the following. By setting the content of the ion scavenger (E) to be equal to or lower than the above upper limit value, the moisture resistance reliability or the reflow resistance of the semiconductor device can be improved.

(hardening accelerator (F))

The resin composition for sealing may contain, for example, a curing accelerator (F). The hardening accelerator (F) may be a crosslinking reaction for promoting the epoxy group of the epoxy resin (A) and the curing agent (B) (for example, a phenolic hydroxyl group of a phenol resin-based curing agent), and for example, The user of the epoxy resin composition for sealing.

In the present embodiment, the curing accelerator (F) may, for example, comprise one or more selected from the group consisting of an organic phosphine, a tetra-substituted fluorene compound, a phosphate betaine compound, an adduct of a phosphine compound and a hydrazine compound. a compound containing a phosphorus atom such as an adduct of a ruthenium compound and a decane compound; exemplified by 1,8-diazabicyclo(5,4,0)undecene-7, dimethylbenzylamine, 2-methylimidazole, and the like A compound containing a nitrogen atom such as a tertiary amine or a quaternary salt of the above hydrazine or amine. Among these, a compound containing a phosphorus atom is more preferable from the viewpoint of improving hardenability. Further, from the viewpoint of improving the balance between formability and hardenability, it is more preferable to contain a tetrasubstituted anthracene compound and a phosphate betaine compound. The compound, the adduct of the phosphine compound and the hydrazine compound, the adduct of the hydrazine compound and the decane compound, and the like are latent.

Examples of the organophosphine which can be used in the resin composition for sealing include a primary phosphine such as ethylphosphine or phenylphosphine; a secondary phosphine such as dimethylphosphine or diphenylphosphine; and trimethylphosphine and triethylamine. A tertiary phosphine such as a phosphine, a tributylphosphine or a triphenylphosphine.

The tetrasubstituted fluorene compound which can be used for the resin composition for sealing is, for example, a compound represented by the following formula (5).

(In the above formula (5), P represents a phosphorus atom. R ⁴ , R ⁵ , R ⁶ and R ⁷ represent an aromatic group or an alkyl group. A represents that the aromatic ring has at least one selected from the group consisting of a hydroxyl group, a carboxyl group, and a thiol. An anion of an aromatic organic acid of any one of the functional groups in the group. AH represents an aromatic organic acid having at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group and a thiol group in the aromatic ring. x, y represents 1~3, z means 0~3, and x=y)

The compound represented by the formula (5) can be obtained, for example, by the following method, but is not limited thereto. First, a tetrasubstituted phosphonium halide, an aromatic organic acid, and a base are mixed in an organic solvent and uniformly mixed to produce an aromatic organic acid anion in the solution. Then, by adding water, the compound represented by the formula (5) can be precipitated. In the compound represented by the formula (5), R ⁴ , R ⁵ , R ⁶ and R ^{7 which} are bonded to the phosphorus atom are preferably a phenyl group, and AH is a compound having a hydroxyl group in the aromatic ring, that is, a phenol. And A is an anion of the phenol. Examples of the phenols include monocyclic phenols such as phenol, cresol, resorcin, and catechol; condensed polycyclic phenols such as naphthol, dihydroxynaphthalene, and stilbene; and bisphenol A. , bisphenols such as bisphenol F and bisphenol S; polycyclic phenols such as phenylphenol and biphenol;

The phosphate betained compound which can be used for the resin composition for sealing is, for example, a compound represented by the following formula (6).

(In the above formula (6), R ⁸ represents an alkyl group having 1 to 3 carbon atoms, and R ⁹ represents a hydroxyl group. f is a number of 0 to 5, and g is a number of 0 to 3)

The compound represented by the formula (6) is obtained, for example, in the following manner. First, a tri-aromatic substituted phosphine as a tertiary phosphine is brought into contact with a diazonium salt, and is obtained by a step of substituting a triaromatic-substituted phosphine with a diazonium group of a diazonium salt. However, it is not limited to this.

The adduct of the phosphine compound and the hydrazine compound which can be used for the resin composition for sealing, for example, a compound represented by the following formula (7), and the like can be mentioned.

(In the above formula (7), P represents a phosphorus atom. R ¹⁰ , R ¹¹ and R ¹² represent an alkyl group having 1 to 12 carbon atoms or an aryl group having 6 to 12 carbon atoms, which may be the same or different from each other. ¹³ , R ¹⁴ and R ¹⁵ represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, which may be the same or different, and R ¹⁴ and R ¹⁵ may be bonded to form a cyclic structure)

As the phosphine compound for the adduct of the phosphine compound and the ruthenium compound, for example, triphenylphosphine, tris(alkylphenyl)phosphine, tris(alkoxyphenyl)phosphine, trinaphthylphosphine, and the like are preferable. The (benzyl)phosphine is equivalent to an unsubstituted aromatic ring or a substituent such as an alkyl group or an alkoxy group. Examples of the substituent such as an alkyl group or an alkoxy group include those having a carbon number of 1 to 6. From the viewpoint of availability, triphenylphosphine is preferred.

Further, examples of the ruthenium compound used for the adduct of the phosphine compound and the ruthenium compound include benzoquinone and anthraquinone. Among them, benzoquinone is preferred in terms of storage stability.

As a method for producing an adduct of a phosphine compound and a hydrazine compound, an adduct can be obtained by contacting and mixing a solvent in which both an organic tertiary phosphine and a benzoquinone are dissolved. As the solvent, a ketone such as acetone or methyl ethyl ketone is preferred, and the solubility in the adduct is preferably low. However, it is not limited to this.

In the compound represented by the formula (7), in terms of the thermal modulus at the time of lowering the heat of the cured product of the resin composition for sealing, R ¹⁰ , R ¹¹ and R ¹² bonded to the phosphorus atom are preferred. A compound which is a phenyl group and wherein R ¹³ , R ¹⁴ and R ¹⁵ are a hydrogen atom, that is, a compound obtained by adding 1,4-benzoquinone to triphenylphosphine.

The adduct of the oxime compound and the decane compound which can be used for the resin composition for sealing, for example, a compound represented by the following formula (8) can be mentioned.

(In the above formula (8), P represents a phosphorus atom, and Si represents a halogen atom. R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ each represent an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group, and mutually In the formula, R ²⁰ is an organic group bonded to a group Y ² and Y ³ , wherein R ²¹ is an organic group bonded to a group Y ⁴ and Y ^{5 ,} and Y ² and Y ³ represent protonicity. The base is a base from which protons are released, and the groups Y ² and Y ^{3 in the} same molecule are bonded to the ruthenium atom to form a chelate structure. Y ⁴ and Y ⁵ represent a proton-donating group which releases protons. a group, and the groups Y ⁴ and Y ^{5 in the} same molecule are bonded to the ruthenium atom to form a chelate structure. R ²⁰ and R ²¹ may be the same or different from each other, and Y ² , Y ³ , Y ⁴ and Y ⁵ may be mutually The same or different. Z ¹ is an organic group having an aromatic ring or a heterocyclic ring, or an aliphatic group)

In the general formula (8), examples of R ¹⁶ , R ¹⁷ , R ¹⁸ and R ¹⁹ include a phenyl group, a methylphenyl group, a methoxyphenyl group, a hydroxyphenyl group, a naphthyl group, and a hydroxynaphthyl group. a benzyl group, a methyl group, an ethyl group, an n-butyl group, an n-octyl group, a cyclohexyl group or the like, and among these, a phenyl group, a methylphenyl group, a methoxyphenyl group, a hydroxyphenyl group, a hydroxynaphthyl group or the like is more preferred. An aromatic group or an unsubstituted aromatic group having a substituent such as an alkyl group, an alkoxy group or a hydroxyl group.

Further, in the formula (8), R ²⁰ is an organic group bonded to Y ² and Y ³ . Similarly, R ²¹ is an organic group bonded to the groups Y ⁴ and Y ⁵ . Y ² and Y ³ are groups in which a proton group is released by a proton, and the groups Y ² and Y ^{3 in the} same molecule are bonded to a ruthenium atom to form a chelate structure. Similarly, Y ⁴ and Y ⁵ are groups in which a proton group is released from a proton, and the groups Y ⁴ and Y ^{5 in the} same molecule are bonded to a ruthenium atom to form a chelate structure. The radicals R ²⁰ and R ²¹ may be the same or different from each other, and the radicals Y ² , Y ³ , Y ⁴ and Y ⁵ may be the same or different from each other. The base represented by -Y ² -R ²⁰ -Y ³ - and Y ⁴ -R ²¹ -Y ⁵ - in the general formula (8) is a base obtained by proton donor releasing two protons The constituent, as the proton donor, is preferably an organic acid having at least two carboxyl groups or hydroxyl groups in the molecule, and more preferably an aromatic compound having at least two carboxyl groups or hydroxyl groups adjacent to the carbon constituting the aromatic ring. More preferably, it is an aromatic compound having at least two hydroxyl groups adjacent to the carbon constituting the aromatic ring, and examples thereof include catechol, pyrogallol, 1,2-dihydroxynaphthalene, and 2,3-dihydroxy group. Naphthalene, 2,2'-biphenol, 1,1'-bi-2-naphthol, salicylic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, chlorodecanoic acid, tannin Acid, 2-hydroxybenzyl alcohol, 1,2-cyclohexanediol, 1,2-propanediol, glycerin, etc., among these, more preferably catechol, 1,2-dihydroxynaphthalene, 2,3 - Dihydroxynaphthalene.

Further, Z ¹ in the formula (8) represents an organic group or an aliphatic group having an aromatic ring or a heterocyclic ring, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. An aliphatic hydrocarbon group such as octyl group or an aromatic hydrocarbon group such as a phenyl group, a benzyl group, a naphthyl group or a biphenyl group; a glycidoxypropyl group, a mercaptopropyl group, an aminopropyl group or the like having a glycidyloxy group, a mercapto group or an amine group; The reactive substituent such as an alkyl group or a vinyl group is more preferably a methyl group, an ethyl group, a phenyl group, a naphthyl group or a biphenyl group in terms of thermal stability.

As a method for producing an adduct of a ruthenium compound and a decane compound, a sulfonate compound such as phenyltrimethoxydecane or a proton donor such as 2,3-dihydroxynaphthalene is added to the flask to which methanol is added, and the mixture is dissolved. Then, a sodium methoxide-methanol solution was added dropwise with stirring at room temperature. Further, a solution prepared by dissolving a tetrasubstituted ruthenium halide such as tetraphenylphosphonium bromide in methanol in advance was added dropwise thereto under stirring at room temperature to precipitate a crystal. The precipitated crystals were filtered, washed with water, and dried in a vacuum to obtain an adduct of a hydrazine compound and a decane compound. However, it is not limited to this.

The content of the hardening accelerator (F) in the resin composition for sealing is preferably, for example, The total amount of the resin composition for sealing is 0.05% by mass or more, and more preferably 0.1% by mass or more. When the content of the curing accelerator (F) is at least the above lower limit value, the deterioration of the curability of the resin composition for sealing can be suppressed. On the other hand, the content of the curing accelerator (F) in the resin composition for sealing is preferably 1% by mass or less, and more preferably 0.8% by mass or less based on the entire resin composition for sealing. By setting the content of the hardening accelerator (F) to be equal to or less than the above upper limit value, it is possible to suppress a decrease in fluidity of the sealing resin composition.

It can also be used in the resin composition for sealing, and further blended as needed: coupling agent; coloring agent such as carbon black and red dan; low-stress component such as polyoxymethylene rubber; natural wax such as carnauba wax, synthetic wax, and stearin A high-grade fatty acid such as zinc acid and a metal salt or a release agent such as paraffin; various additives such as aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, phosphazene, and the like, and an antioxidant. As the coupling agent, one or two or more kinds of decane-based compounds such as epoxy decane, amino decane, alkyl decane, ureido decane, vinyl decane, methacryl decyl decane, titanium compounds, and aluminum chelate can be used. Known coupling agents exemplified for the materials and aluminum/zirconium compounds.

As a resin composition for sealing, for example, the above-mentioned respective components may be mixed by a known means, and further melt-kneaded by a kneading machine such as a roll, a kneader or an extruder, and then pulverized after cooling; or as appropriate Adjust the dispersion or fluidity.

Next, the semiconductor device 100 of the present embodiment will be described.

The semiconductor device 100 includes a semiconductor element 20, a bonding wire 40, and a sealing resin 50. The bonding wire 40 is connected to the semiconductor element 20 with Cu as a main component. Further, the sealing resin 50 is composed of a cured product of the sealing resin composition, and seals the semiconductor element 20 and the bonding wire 40.

The semiconductor element 20 is mounted on the substrate 30. The substrate 30 is, for example, a lead frame Or an organic substrate. Further, the substrate 30 is connected to the bonding wire 40. FIG. 1 illustrates a case where the semiconductor element 20 is mounted on the die pad 32 in the substrate 30 as the lead frame via the die attach material 10. The base material 30 as the lead frame is made of, for example, a metal material containing Cu or a 42 alloy as a main component. Furthermore, the semiconductor element 20 may be disposed on other semiconductor elements.

On the upper surface of the semiconductor element 20, for example, a plurality of electrode pads 22 are formed. At least the surface layer of the electrode pad 22 provided on the semiconductor element 20 is made of, for example, a metal material containing Al as a main component. Thereby, the connection reliability of the bonding wire 40 with Cu as a main component and the electrode pad 22 can be improved.

In FIG. 1, a case where the bonding wires 40 electrically connect the electrode pads 22 of the semiconductor element 20 to the external leads 34 of the substrate 30 is exemplified.

The sealing resin 50 is composed of a cured product of the above-described sealing resin composition. Therefore, the adhesion to the base material 30 or the bonding wire 40 is good, and the semiconductor device 100 excellent in reflow resistance, high-temperature storage characteristics, moisture resistance reliability, and high-temperature operation characteristics can be obtained. This effect is more remarkable when the bonding wire 40 is composed of a metal material containing Cu as a main component, and the substrate 30 is an organic substrate or a metal material (lead frame) containing Cu or a 42 alloy as a main component. The material 30 is particularly well obtained in the case of a metallic material (lead frame).

The semiconductor device 100 is manufactured, for example, as follows.

First, the semiconductor element 20 is mounted on the substrate 30. Then, the substrate 30 and the semiconductor element 20 are connected to each other by a bonding wire 40 having Cu as a main component. Then, the semiconductor element 20 and the bonding wire 40 are sealed by the sealing resin composition. The method of sealing molding is not particularly limited, and examples thereof include a transfer molding method and a compression molding method. Thereby, the semiconductor device 100 is manufactured.

Further, the present invention is not limited to the above-described embodiments, and modifications, improvements, etc. within a range that can achieve the object of the invention are included in the present invention.

Example

Next, an embodiment of the present invention will be described.

(resin composition for sealing)

For each of Examples 1 to 12 and Comparative Examples 1 and 2, a resin composition for sealing was prepared as follows. First, the filler (D) was subjected to surface treatment by the blending amount of the sulfur-containing compound (C) shown in Table 1. Then, according to the blending shown in Table 1, the components were mixed at 15 to 28 ° C using a mixer. Then, the obtained mixture was subjected to roll kneading at 70 to 100 °C. Then, the kneaded mixture was cooled and pulverized to obtain a resin composition for sealing. In addition, the details of each component in Table 1 are as follows. Further, the unit in Table 1 is mass%.

(A) Epoxy resin

Epoxy Resin 1: Phenol aralkyl type epoxy resin containing extended biphenyl skeleton (NC-3000P, manufactured by Nippon Kayaku Co., Ltd.)

Epoxy Resin 2: Biphenyl type epoxy resin (YX4000K, manufactured by Mitsubishi Chemical Corporation)

(B) hardener

Hardener 1: Phenol aralkyl resin containing a biphenyl skeleton (MEH-7851SS, manufactured by Megumi Kasei Co., Ltd.)

Hardener 2: Phenol aralkyl resin containing a pendant phenyl skeleton (XLC-4L, manufactured by Mitsui Chemicals Co., Ltd.)

(C) sulfur compounds

Γ-mercaptopropyltrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-803)

(D) filler

Filler 1: cerium oxide (average particle size 26 μm, specific surface area 2.4 mm ² /g)

Filler 2: cerium oxide (SO-25R, manufactured by Admatechs, average particle size 0.5 μm, specific surface area 6.0 mm ² /g)

(E) ion trapping agent

Hydrotalcite (DHT-4H, manufactured by Xiehe Chemical Industry Co., Ltd.)

(F) hardening accelerator

Hardening accelerator 1: a compound represented by the following formula (9)

Hardening accelerator 2: a compound represented by the following formula (10)

(G) release agent

Carnauba wax

In Examples 1 to 4, 7 to 12, and Comparative Examples 1 and 2, the surface treatment of the filler (D) by the sulfur-containing compound (C) was carried out as follows. First, filler 1 and filler 2 After the mixture was introduced into the mixer, stirring was started, and the sulfur-containing compound (C) was further added thereto, and the mixture was stirred for 3.0 minutes to obtain a mixture of the filler 1, the filler 2, and the sulfur-containing compound (C). Then, the mixture was taken out from the mixer, and the time shown in Table 1 (the standing time after the spraying) was placed. Thereby, the filler (D) which has been surface-treated by the sulfur-containing compound (C) is obtained.

In the same manner as in Example 1, the surface mixture was treated in the same manner as in Example 1 except that the mixture was subjected to heat treatment at 55 ° C for 3 hours.

In the same manner as in Example 1, except that the mixture of the filler 1, the filler 2 and the sulfur-containing compound (C) was obtained in the following manner, the surface treatment was carried out in the same manner as in Example 1. First, the filler 1 and the filler 2 are put into a mixer, and these are mixed. Then, the sulfur-containing compound (C) was sprayed on the filler 1 and the filler 2 in the mixer using a sprayer, and the mixture was stirred for 3.0 minutes to obtain a filler 1, a filler 2, and a sulfur-containing compound (C). a mixture of). Then, the mixture was taken out from the mixer, and the time shown in Table 1 (the standing time after the spraying) was placed.

(Measurement of expansion ratio S)

With respect to each of Examples 1 to 12 and Comparative Examples 1 and 2, the obtained expansion resin composition was used, and the expansion ratio S was measured as follows. 2 is a cross-sectional view for explaining a method of measuring the expansion ratio.

First, the sealing resin composition was thermally cured at 175 ° C for 4 hours, and the obtained cured product was pulverized to obtain a pulverized product 80. In the pulverization treatment, 5 g of the cured product was placed in a pulverizer by using TI-100 (manufactured by CMT Co., Ltd.), and pulverization was carried out for 2 minutes. Then, as shown in FIG. 2, 1.0 g of the obtained pulverized material 80 and the structure 60 composed of the lead frame 64 and the semiconductor wafer 66 connected to each other via the Cu wire 62 (4N grade) are used to make the Cu wire 62. The whole was exposed to air and placed in a sealed container 70 of a glass petri dish having an inner diameter of 50 mm and a height of 17 mm, and heat-treated under an air atmosphere at 200 ° C for 96 hours. Further, the maximum diameter D ₀ of the center point of the Cu wire 62 before the heat treatment was 20 μm. Further, the lead frame 64 is fixed in the hermetic container 70 by using the Kapton tape 90. Then, the maximum diameter D ₁ of the center point of the Cu wire 62 after the heat treatment was measured, and the expansion ratio S = D ₁ / D ₀ × 100 (%) was calculated from the obtained result. The results are shown in Table 1.

(Production of semiconductor device)

For each of Examples 1 to 12 and Comparative Examples 1 and 2, a semiconductor device was produced as follows.

First, a TEG (Test Element Group) wafer (3.5 mm × 3.5 mm) equipped with an aluminum electrode pad was mounted on a die pad portion of a lead frame whose surface was plated with Ag. Then, using a bonding wire made of a metal material of 99.9% of Cu, the electrode pads of the TEG wafer (hereinafter referred to as electrode pads) and the lead portions outside the lead frame were wire-bonded at a line pitch of 120 μm. Using the low-pressure transfer molding machine, the thus obtained structure was subjected to sealing molding using a resin composition for sealing at a mold temperature of 175 ° C, an injection pressure of 10.0 MPa, and a curing time of 2 minutes to prepare a semiconductor package. Thereafter, the obtained semiconductor was packaged and cured at 175 ° C for 4 hours to obtain a semiconductor device.

(MSL (Reflow Resistance Evaluation))

For each of Examples 1 to 12 and Comparative Examples 1 and 2, the obtained semiconductor devices were placed in an environment of 60% relative humidity of 60% for 168 hours, and then subjected to IR reflow treatment (260 ° C). Then, the inside of the semiconductor device after the treatment was observed by the ultrasonic flaw detector to calculate the area where the interface between the sealing resin and the lead frame was peeled off. For all semiconductor devices, the case where the peeling area is less than 5% is ◎, and the case where 5% or more and 10% or less is ○, and more than 10% The case is set to ×.

(HTSL (High Temperature Storage Characteristics Evaluation))

For each of Examples 1 to 12 and Comparative Examples 1 and 2, the obtained semiconductor device was stored in an environment of 150 ° C, and the resistance value between the electrode pads of the semiconductor wafer and the bonding wires was measured every 24 hours. A semiconductor device whose value is increased by 20% from the initial value is set to be defective. If it is stored for 2,000 hours, it will be ◎ if there is no defect, ○ will be caused by a defect between 1000 and 2000 hours, and × will be caused by a defect within 1000 hours.

As shown in Table 1, in Examples 1 to 12, good results were obtained regarding the reflow resistance and the high-temperature storage characteristics. Examples 1 to 6, 8, 10, and 12 exhibited superior high-temperature storage characteristics as compared with Examples 7, 9, and 11. Further, Examples 2 to 12 exhibited more excellent reflow resistance than Example 1.

The priority of the Japanese Patent Application No. 2014-060297, filed on March 24, 2014, the entire disclosure of which is hereby incorporated by reference.

10‧‧‧ die adhesion material

20‧‧‧Semiconductor components

22‧‧‧electrode pads

30‧‧‧Substrate

32‧‧‧ die holder

34‧‧‧External leads

40‧‧‧bonding line

50‧‧‧ sealing resin

60‧‧‧structure

100‧‧‧Semiconductor device

Claims (4)

A sealing resin composition for sealing a semiconductor element and a bonding wire connected to the semiconductor element and containing Cu as a main component, the sealing resin composition containing an epoxy resin, a hardener, and sulfur In the compound, the expansion ratio S calculated under the following condition 1 is 150% or less. (Condition 1: The sealing resin composition is thermally cured at 175 ° C for 4 hours, and the obtained cured product is pulverized. Then, a pulverized material was obtained; and then, 1.0 g of the pulverized material and a structure composed of a lead frame and a semiconductor wafer which were connected to each other via a Cu wire (maximum diameter D ₀ = 20 μm at the center point) were used to make the Cu wire. It is placed in a closed container by exposure to air, and heat-treated under an air atmosphere at 200 ° C for 96 hours. Then, the maximum diameter D ₁ of the center point of the Cu wire is measured, and the expansion is calculated from the obtained result. Rate S = D ₁ / D ₀ × 100 (%)). The resin composition for sealing according to the first aspect of the invention, which further comprises an ion scavenger. The resin composition for sealing according to the second aspect of the invention, wherein the ion trapping agent is contained in an amount of 0.05% by mass or more and 1% by mass or less based on the total amount of the resin composition for sealing. A semiconductor device comprising: a semiconductor element; a bonding wire connected to the semiconductor element and containing Cu as a main component; and a sealing resin which is a sealing resin according to any one of claims 1 to 3. A cured product of the composition is formed, and the semiconductor element is sealed to the bonding wire.