JP5480560B2 - Adhesive for joining electronic components - Google Patents

Description

The present invention relates to an episulfide compound having low crystallinity and excellent quick curability.

Conventionally, when a semiconductor product is manufactured using a semiconductor chip, a process (die bonding process) in which the semiconductor chip is bonded and fixed to a substrate or the like using an adhesive is performed.
As an adhesive used in such a die bonding step, for example, Patent Document 1 discloses a die attach paste containing an epoxy resin, a phenol aralkyl resin, an imidazole compound, and the like. Patent Document 1 describes that the die attach paste described in the same document is excellent in adhesiveness, fast curability, and reliability, and that high adhesion reliability can be obtained by curing in a short time. In the Example of patent document 1, the adhesive strength at the time of making it harden | cure at 200 degreeC, 30 second, and 60 second is evaluated.

In recent years, there has been an increasing demand for higher integration of semiconductor packages, and semiconductor chips have been stacked in multiple layers. For this reason, using an adhesive that requires several tens of seconds for curing, such as the die attach paste described in Patent Document 1, there is a problem that the time required to manufacture one semiconductor package becomes longer. It was happening. In addition, due to the multi-layer stacking, a slight chip shift can be a fatal defect as a stacked body, but there is also a problem that a shift is likely to occur if it takes too much time for curing.

In order to eliminate the prolonged manufacturing time of the semiconductor package, for example, the use of an episulfide compound as a curable compound has been studied. An episulfide compound is a compound having a thiirane ring in which an oxygen atom on the oxirane ring is substituted with a sulfur atom, and is known as a curable compound having a relatively high curing rate.
However, the rapid curing properties of conventional episulfide compounds are not yet sufficient, and a curable compound having excellent rapid curing properties that can sufficiently cope with the multilayer lamination of semiconductor chips is desired. In addition, conventional episulfide compounds, especially episulfide compounds having a benzene ring, have high crystallinity. Adhesives containing such episulfide compounds increase in viscosity over time, resulting in a decrease in coatability. Met.

JP 2004-172443 A

An object of the present invention is to provide an episulfide compound having low crystallinity and excellent quick curability.

The present invention is an episulfide compound having a structure represented by the following general formula (1).

In general formula (1), at least one of R ^{1 to} R ¹⁰ represents a thiirane ring-containing group, and R ^{1 to} R ¹⁰ other than the thiirane ring-containing group represent a hydrogen atom or an alkyl group, They may be the same or different.
The present invention is described in detail below.

The present inventors have found that an episulfide compound having a specific structure has low crystallinity and is excellent in rapid curability. The present inventors have significantly shortened the time (tact time) required for the production of electronic components because the adhesive containing the episulfide compound does not thicken over time and is excellent in rapid curing. The present inventors have found that the present invention can be accomplished and have completed the present invention.

The episulfide compound of the present invention has a structure represented by the following general formula (1).

In general formula (1), at least one of R ^{1 to} R ¹⁰ represents a thiirane ring-containing group, and R ^{1 to} R ¹⁰ other than the thiirane ring-containing group represent a hydrogen atom or an alkyl group, They may be the same or different.

In the general formula (1), at least one of R ^{1 to} R ¹⁰ represents a thiirane ring-containing group.
The thiirane ring-containing group is not particularly limited as long as it has at least one thiirane ring in the molecule, and examples thereof include a functional group having an alkyl group or an alkyl ether group in addition to the thiirane ring. Of these, a thiirane ring-containing group having a structure represented by the following formula (A) is preferable.

In the general formula (1), at least one of R ¹ to R ¹⁰ may if thiirane ring-containing group, but it more than two of R ¹ to R ¹⁰ is a thiirane ring-containing group preferable. When two or more of R ^{1 to} R ¹⁰ are thiirane ring-containing groups, when joining electronic parts using an adhesive containing an episulfide compound, quick curability is improved and connection reliability is improved. Can be obtained.

In the general formula (1), R ^{1 to} R ¹⁰ other than the thiirane ring-containing group represent a hydrogen atom or an alkyl group.
The alkyl group is not particularly limited, and examples thereof include a methyl group, an ethyl group, and a propyl group.

The episulfide compound of the present invention preferably has a structure represented by the following formula (1-1). By having the structure represented by the following formula (1-1), the episulfide compound has low crystallinity and excellent quick curability, and further, an electronic component using an adhesive containing such an episulfide compound. When joining, a joined body with high connection reliability can be obtained.

The method for producing the episulfide compound of the present invention is not particularly limited. For example, first, an epoxy compound having an oxirane ring instead of the thiirane ring of the target episulfide compound is produced, and then obtained in the presence of a solvent. A method of converting an oxirane ring into a thiirane ring by reacting an epoxy compound with a sulfurizing agent can be mentioned.
There is also provided a method for producing an episulfide compound of the present invention, wherein the oxirane ring of the epoxy compound is converted to a thiirane ring by reacting the epoxy compound with a sulfurizing agent in the presence of a solvent. This is one of the present inventions.

The solvent is not particularly limited, and for example, commonly used solvents such as methanol, ethanol, propanol, methylene chloride, toluene, methyl acetate, ethyl acetate, acetone, dimethyl ketone, methyl ethyl ketone, and methyl isobutyl ketone can be used.

The said epoxy compound is an epoxy compound which has an oxirane ring instead of the thiirane ring of the target episulfide compound. By reacting such an epoxy compound with a sulfurizing agent, the oxygen atom on the oxirane ring of the epoxy compound is replaced with a sulfur atom, whereby the oxirane ring can be converted to a thiirane ring to produce an episulfide compound. .
Specifically, for example, when producing an episulfide compound having a structure represented by the above formula (1-1), the epoxy compound has a structure represented by the following formula (1-2).

The method for producing the epoxy compound having the structure represented by the above formula (1-2) is not particularly limited. For example, a hydroxyl group is substituted for the glycidyl liter in the structure represented by the above formula (1-2). The method which makes a hydroxyl group glycidyl ether by making epichlorohydrin react with the compound which has is mentioned.
In addition, it can confirm that the epoxy compound which has a structure represented by the said Formula (1-2) was obtained by measuring NMR.

The sulfurizing agent is not particularly limited, and examples thereof include thiocyanates such as potassium thiocyanate, thiourea, and the like.
Although the addition amount of the said sulfurizing agent is not specifically limited, The preferable minimum with respect to 100 weight part of said epoxy compounds is 5 weight part, and a preferable upper limit is 200 weight part. When the addition amount of the sulfiding agent is less than 5 parts by weight, substitution from oxygen atoms to sulfur atoms may not sufficiently proceed. When the addition amount of the sulfiding agent exceeds 200 parts by weight, the obtained episulfide compound may self-polymerize.
In addition, it can confirm by measuring NMR that the oxygen atom on the oxirane ring of the said epoxy compound was substituted by the sulfur atom.

The episulfide compound of the present invention has low crystallinity and excellent quick curability. Therefore, the adhesive containing the episulfide compound of the present invention does not thicken over time, maintains good coatability, is excellent in fast curability, and is involved in the production of electronic components. Time (tact time) is significantly shortened.

Further, when the episulfide compound of the present invention and a compound in which a part or all of the thiirane ring of the episulfide compound of the present invention is not a thiirane ring and is an oxirane ring that is less reactive than a thiirane ring are used in combination. The mixture of these compounds is excellent in stability while maintaining excellent rapid curability.
An episulfide-epoxy mixture containing the episulfide compound of the present invention and a compound in which at least one of the thiirane rings of the episulfide compound of the present invention is an oxirane ring, comprising the thiirane ring and the oxirane ring in the mixture Episulfide-epoxy mixtures with a ratio of 1: 3 to 3: 1 are also one aspect of the present invention.

In addition to the episulfide compound of the present invention, the episulfide-epoxy mixture of the present invention includes a compound in which at least one of the thiirane rings of the episulfide compound of the present invention is an oxirane ring (hereinafter also referred to as a compound having an oxirane ring). contains.
The compound having an oxirane ring may be a compound in which at least one of the thiirane rings of the episulfide compound of the present invention is an oxirane ring, and may have both a thiirane ring and an oxirane ring in the molecule. It may have only an oxirane ring. In addition, the episulfide-epoxy mixture of this invention may contain only 1 type as a compound which has the said oxirane ring, and may contain 2 or more types.

In the episulfide-epoxy mixture of the present invention, the content ratio of thiirane ring and oxirane ring in the mixture is 1: 3 to 3: 1. When the content of the thiirane ring in the episulfide-epoxy mixture of the present invention is less than 1/3 of the content of the oxirane ring, the rapid curability of the episulfide-epoxy mixture decreases. When the content of thiirane ring in the episulfide-epoxy mixture of the present invention exceeds 3 times the content of oxirane ring, the stability of the episulfide-epoxy mixture decreases, and an adhesive containing such an episulfide-epoxy mixture becomes , Storage stability decreases.
In addition, the content ratio of the thiirane ring and the oxirane ring in the episulfide-epoxy mixture of the present invention can be confirmed by measuring NMR.

The episulfide-epoxy mixture of the present invention includes an episulfide compound having a structure represented by the above formula (1-1), a compound having a structure represented by the above formula (1-2), and the following formula (1-3) ) And a compound having a structure represented by the following formula (1-4). By containing these compounds, the episulfide-epoxy mixture has low crystallinity, excellent quick curability and stability, and further, an adhesive containing such an episulfide-epoxy mixture is used. When joining electronic parts etc., a joined body with high connection reliability can be obtained.

Similar to the episulfide compound of the present invention, the episulfide-epoxy mixture of the present invention has low crystallinity and excellent rapid curability. Therefore, the adhesive containing the episulfide-epoxy mixture of the present invention does not thicken over time, maintains good coatability, has excellent fast curability, and produces electronic components. The time (tact time) required for remarkably shortens. Furthermore, the adhesive which mix | blended the episulfide-epoxy mixture of this invention is excellent also in storage stability.

Although the use of the episulfide compound and the episulfide-epoxy mixture of the present invention is not particularly limited, it can be suitably applied to an electronic component bonding adhesive used when a semiconductor chip is bonded to a substrate or another semiconductor chip. The episulfide compound and episulfide-epoxy mixture of the present invention are also suitable for anisotropic conductive adhesives (ACP) for conductively connecting a semiconductor chip and a substrate or another semiconductor chip with conductive fine particles contained in the adhesive. Can be applied to.
An adhesive for bonding electronic parts and an anisotropic conductive adhesive containing the episulfide compound or episulfide-epoxy mixture of the present invention are also one aspect of the present invention.

The electronic component bonding adhesive and anisotropic conductive adhesive of the present invention are excellent in rapid curing, and specifically, can be cured by heating at about 150 to 200 ° C. for 1 to 10 seconds. Therefore, the tact time can be remarkably shortened. In addition, since the adhesive for bonding electronic parts and the anisotropic conductive adhesive of the present invention can be cured at a relatively low temperature, when used for bonding thin electronic parts, there is also an effect of suppressing the occurrence of warpage. It can be demonstrated.
Furthermore, the adhesive for bonding electronic parts according to the present invention can complete the curing within 5 seconds when heating at about 240 to 260 ° C., which is the melting point region of the solder alloy for connection. It is also suitably used as an NCP used in flip chip connection of chips, lamination of semiconductor chips having through electrodes, and the like.
In the present specification, completion of curing means that adherends have a shear strength of 0.1 N / mm or more at room temperature.

According to the present invention, an episulfide compound having low crystallinity and excellent quick curability can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(Production of Episulfide Compound A)
In a flask, 100 g of benzophenone type epoxy (EP-3300S, manufactured by Adeka Corporation, epoxy equivalent = 180 g / eq.) And 100 g of tetrahydrofuran were charged and stirred at room temperature to dissolve the epoxy compound. After dissolution, 60 g of thiourea and 400 g of methanol were added and reacted at a temperature of 30 to 35 ° C. with stirring for 5 hours. After completion of the reaction, 900 g of methyl isobutyl ketone was added, and then washed 5 times with 250 g of pure water. After washing with water, methyl isobutyl ketone was distilled off at 90 ° C. under reduced pressure using a rotary evaporator to obtain 57 g of colorless and transparent liquid episulfide compound A. The thiirane ring conversion rate of the episulfide compound A obtained from the NMR measurement result was 93%.

(Preparation of adhesive for electronic parts)
50 parts by weight of the obtained episulfide compound A, 50 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent = 185 g / eq.), And an imidazole curing agent (TEP-2E4MZ, 8 parts by weight of Nippon Soda Co., Ltd.) was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

(Example 2)
(Preparation of adhesive for electronic parts)
85 parts by weight of the obtained episulfide compound A, 15 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent = 185 g / eq.), Imidazole-based curing agent (TEP-2E4MZ, 8 parts by weight of Nippon Soda Co., Ltd.) was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

(Example 3)
(Production of episulfide compound B)
In a flask, 100 g of benzophenone type epoxy (EP-3300S, manufactured by Adeka Corporation, epoxy equivalent = 180 g / eq.) And 100 g of tetrahydrofuran were charged and stirred at room temperature to dissolve the epoxy compound. After dissolution, 60 g of thiourea and 400 g of methanol were added, and the reaction was performed at a temperature of 30 to 35 ° C. with stirring for 3 hours. After completion of the reaction, 900 g of methyl isobutyl ketone was added, and then washed 5 times with 250 g of pure water. After washing with water, methyl isobutyl ketone was distilled off at 90 ° C. under reduced pressure using a rotary evaporator to obtain 89 g of colorless and transparent liquid episulfide compound B. The thiirane ring conversion rate of the episulfide compound B obtained from the NMR measurement result was 52%.

(Preparation of adhesive for electronic parts)
50 parts by weight of the obtained episulfide compound B, 50 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent = 185 g / eq.), And an imidazole-based curing agent (TEP-2E4MZ, 8 parts by weight of Nippon Soda Co., Ltd.) was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

Example 4
(Production of episulfide compound C)
In a flask, 100 g of benzophenone type epoxy (EP-3300S, manufactured by Adeka Corporation, epoxy equivalent = 180 g / eq.) And 100 g of tetrahydrofuran were charged and stirred at room temperature to dissolve the epoxy compound. After dissolution, 20 g of thiourea and 400 g of methanol were added, and the reaction was performed at a temperature of 30 to 35 ° C. with stirring for 3 hours. After completion of the reaction, 900 g of methyl isobutyl ketone was added, and then washed 5 times with 250 g of pure water. After washing with water, methyl isobutyl ketone was distilled off at 90 ° C. under reduced pressure on a rotary evaporator to obtain 92 g of episulfide compound C as a colorless transparent liquid. The thiirane ring conversion rate of the episulfide compound C obtained from the NMR measurement result was 21%.

(Preparation of adhesive for electronic parts)
90 parts by weight of the obtained episulfide compound C, 10 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent = 185 g / eq.), And an imidazole curing agent (TEP-2E4MZ, 8 parts by weight of Nippon Soda Co., Ltd.) was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

(Example 5)
(Preparation of adhesive for electronic parts)
50 parts by weight of the obtained episulfide compound C, 50 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent = 185 g / eq.), And an imidazole curing agent (TEP-2E4MZ, 8 parts by weight of Nippon Soda Co., Ltd.) was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

(Comparative Example 1)
(Production of episulfide compound D)
In a flask, 100 g of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin, epoxy equivalent = 185 g / eq.) And 100 g of tetrahydrofuran were charged, and stirred at room temperature to dissolve the epoxy compound. After dissolution, 60 g of thiourea and 400 g of methanol were added and reacted at a temperature of 30 to 35 ° C. with stirring for 5 hours. After completion of the reaction, 900 g of methyl isobutyl ketone was added, and then washed 5 times with 250 g of pure water. After washing with water, methyl isobutyl ketone was distilled off at 90 ° C. under reduced pressure using a rotary evaporator to obtain 85 g of episulfide compound D as a colorless transparent liquid. The thiirane ring conversion rate of the episulfide compound D obtained from the NMR measurement result was 92%.

(Preparation of adhesive for electronic parts)
50 parts by weight of the obtained episulfide compound D, 50 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent = 185 g / eq.), And an imidazole curing agent (TEP-2E4MZ, 8 parts by weight of Nippon Soda Co., Ltd.) was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

(Comparative Example 2)
(Preparation of adhesive for electronic parts)
100 parts by weight of bisphenol A type epoxy (YL-980, manufactured by Japan Epoxy Resin, epoxy equivalent = 185 g / eq.) And 8 parts by weight of imidazole-based curing agent (TEP-2E4MZ, manufactured by Nippon Soda Co., Ltd.) The mixture was stirred and mixed using a homodisper to prepare an adhesive for joining electronic components.

(Evaluation)
The following evaluation was performed about the adhesive agent for electronic component joining obtained by the Example and the comparative example. The results are shown in Table 1.
(1) For the viscosity increase the electronic component bonding adhesive, at 23 ° C., E-type viscometer (trade name VISCOMETER TV-22, TOKI SANGYO CO.LTD Co., using rotor 15 mm) initial viscosity using eta ₀ ( Pa · s) and viscosity η _t (Pa · s) after 48 hours from the preparation were measured. The value of η _t / η ₀ was evaluated as the rate of increase in viscosity.

(2) Measurement of gelation time About 0.1 mL of adhesive for bonding electronic parts is dropped on a hot plate, and the glass that has been heated on the hot plate set to 150 ° C. and 200 ° C. in advance is heated from above. Pressed. The time until the glass did not come off was measured as the gel time.

(3) Curing characteristics at 200 ° C. for 5 seconds 10 mm × 10 mm, 80 μm thick semiconductor chip and 20 mm × 20 mm, 170 μm thick substrate (manufactured by Daisho Electronics Co., Ltd.) It was applied to a thickness of 10 μm. Using a flip chip bonder manufactured by Sugaya Kogyo Co., Ltd., the adhesive temperature during bonding was set to 200 ° C., and it was observed whether it could be cured by heating bonding for 5 seconds. At this time, the stage temperature was set to 80 ° C., the tool temperature was set to 220 ° C., and a collet of SiN was used as the collet.
The case where the curing was completed was evaluated as “◯”, and the case where the curing was not completed was evaluated as “x”. In this evaluation, “curing is complete” means that the shear strength is 0.1 N / mm or more, and “hardening is not complete” means that the shear strength is less than 0.1 N / mm. means.

According to the present invention, an episulfide compound having low crystallinity and excellent quick curability can be provided.

Claims (1)

An adhesive for joining electronic parts, comprising an episulfide compound having a structure represented by the following formula (1-1) and a curing agent.