KR100798677B1 - Epoxy resin composition for encapsulating semiconductor device and semiconductor device??using the same - Google Patents

Abstract

An epoxy resin composition for packaging a semiconductor device is provided to reduce the problem of separation between the surface of a wafer chip and an epoxy packaging material and to reduce cracking of a pad surface and a chip. An epoxy resin composition comprises 0.1-5 wt% of an isocyanate terminated polyurethane prepolymer represented by the formula 1; 0.1-10.7 wt% of a polyaromatic epoxy resin represented by the formula 2; 0.1-7.3 wt% of a polyaromatic curing agent represented by the formula 4; 0.1-1.5 wt% of a triazine-based resin represented by the formula 6; 0.05-0.5 wt% of a curing accelerator; and 75-95 wt% of an inorganic filler. In the formula 1, R is a hydroxyl group or a methyl group; and n is an integer of 1-10. In the formulae 2 and 4, R1 and R2 are identical or different each other and are a C1-C4 alkyl group; a is an integer of 0-4; and n is an integer of 1-7.

Description

Epoxy resin composition for encapsulating semiconductor device and semiconductor device using the same}

The present invention relates to a resin composition for sealing semiconductor elements, and more particularly, it is possible to secure flame retardancy without using a halogen-based flame retardant or a phosphorus-based flame retardant, to improve a crack problem occurring on a pad surface and a chip, and an epoxy encapsulant. The present invention relates to an epoxy resin composition for sealing semiconductor elements which maintains high reliability by reducing the peeling occurring between the surface and the surface.

In general, flame retardancy is required in manufacturing an epoxy resin for semiconductor encapsulant, and most semiconductor companies require UL-94 V-0 as flame retardant. In order to secure such flame retardancy, a flame retardant is used to manufacture an epoxy resin for a semiconductor encapsulant, and bromine epoxy and antimony trioxide are mainly used to prepare an epoxy resin for a semiconductor encapsulant to ensure flame retardancy. However, in the case of an epoxy resin for a semiconductor encapsulant having flame retardancy by using a halogen-based flame retardant, it is known that toxic carcinogens such as dioxin or difuran are generated during incineration or fire. In addition, halogen-based flame retardants are toxic to humans due to gases such as HBr and HCl generated during combustion, and are the main cause of corrosion of semiconductor chips, wires, and lead frames. There is a problem such as working. As a countermeasure, new flame retardants such as phosphorus-based flame retardants such as phosphazene and phosphate esters and nitrogen-containing resins have been considered. However, in the case of nitrogen-containing resins, the flame retardancy is insufficient. In addition, polyphosphoric acid may cause cracks on the pad surface and the chip in a post-semiconductor process, thereby causing a problem of deteriorating the reliability of the semiconductor.

An object of the present invention for solving the above problems is to apply an isocyanate terminated polyurethane prepolymer, the epoxy resin composition for sealing a semiconductor device that is improved thermal shock, especially crack problems occurring on the pad surface and chip in the post-semiconductor process To provide.

Another object of the present invention is to improve the peeling problem between the wafer chip surface and the epoxy encapsulant in the semiconductor device encapsulation process by using a triazine-based resin containing at least one mercapto group at the terminal end as an adhesion increasing agent. It is providing the epoxy resin composition for sealing semiconductor elements to provide.

It is still another object of the present invention to provide an epoxy resin composition for sealing semiconductor devices, which is flame retardant by using a multi-aromatic epoxy resin and a multi-aromatic curing agent without using a halogen-based flame retardant and a phosphorus-based flame retardant, which are harmful to a human body or a device.

The epoxy resin for sealing a semiconductor device of the present invention for achieving the above object is 0.1 to 5% by weight of isocyanate terminated polyurethane prepolymer represented by the following general formula (1), 0.1 to 10.7 polyaromatic epoxy resin represented by the following general formula (2) 0.1 wt% to 7.3 wt% of the polyaromatic curing agent represented by the following formula (4), 0.01 wt% to 1.5 wt% of the triazine resin represented by the following Formula (6), 0.05 wt% to 0.5 wt% of the curing accelerator, and 75 wt% to 95 wt% of the inorganic filler. It is characterized by including.

[Formula 1]

(Wherein R is a hydrogen atom or a methyl group and n is an integer from 1 to 10).

[Formula 2]

(In the formula, R1, R2 is an alkyl group having 1 to 4 carbon atoms.

good. a is an integer of 0 to 4 and n is a number between 1 and 7)

[Formula 4]

(In the formula, R1, R2 is an alkyl group having 1 to 4 carbon atoms.

good. a is an integer of 0 to 4 and n is a number between 1 and 7)

[Formula 6]

(Wherein R is the same or different mercapto group, alkyl group, or amine group, respectively.)

In addition, the triazine resin is 2-dibutylamino-4,6-dimercapto-S-triazine, 2-dibutylamino-mercapto-triazine, 2-anilino-4,6-dimercapto-S It is characterized in that at least one selected from the group consisting of -triazine, 2,4,6-trimercupto-S-triazine.

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In addition, the curing accelerator is a triazine isocyanate imidazole compound, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, tetraphenylboron salt and the like as a triphenylphosphine adduct, benzyldimethylamine, triethanolamine, tri It is characterized by being at least one selected from amine compounds such as ethylenediamine, dimethylaminoethanol, tri (dimethylaminomethyl) phenol and phosphine compounds such as triphenylphosphine, diphenylphosphine and phenylphosphine.

In addition, the composition is characterized by using a isocyanate-type latent curing catalyst as a curing accelerator, and further using an amine type cocatalyst or a phosphine type cocatalyst.

In addition, the inorganic filler may have a spherical silica having a mean particle size of 0.1 to 2 μm, and 3 to 10 wt% of the whole inorganic filler in the composition, and a spherical silica having a mean particle size of 3 to 9 μm. It is characterized by using spherical silica of 20 weight% and an average particle diameter of 10-20 micrometers in mixture of 70 to 92 weight% of the whole inorganic filler in a composition.

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In addition, the above-mentioned epoxy resin composition for semiconductor element sealing is mixed using a Henschel mixer or a solid mixer, melt-kneaded with a roll mill or a kneader, and then sealed with a final powder product obtained through cooling and grinding. Provided is an element.

Hereinafter, the present invention will be described in more detail.

The epoxy resin composition for semiconductor element sealing of this invention uses a polyaromatic epoxy resin and a polyaromatic hardening | curing agent as a basic resin, and introduces an isocyanate terminated polyurethane prepolymer as a basic structure.

The isocyanate terminated polyurethane prepolymer is represented by the following Chemical Formula 1, and serves to improve the adhesiveness between the wafer chip surface and the encapsulation material and crack resistance of the package in a high temperature solder process of 240 ° C to 265 ° C.

[Formula 1]

(Wherein R is a hydrogen atom or a methyl group and n is an integer from 1 to 10).

The weight average molecular weight of the isocyanate terminated polyurethane prepolymer is preferably 1,000 to 10,000, more preferably 1,150 to 4,600.

The content of the isocyanate terminated polyurethane prepolymer is preferably in the range of 0.1 to 5% by weight relative to the total composition, more preferably 0.2 to 2% by weight. If the content is less than 0.1% by weight it may be difficult to achieve a sufficient physical property modification effect, if it exceeds 5% by weight it may be difficult to secure a uniform crosslinking reaction and to provide adhesion.

The polyaromatic epoxy resin used in the composition of the present invention has a structure represented by the following formula (2).

[Formula 2]

(Wherein R1 and R2 are alkyl groups having 1 to 4 carbon atoms, which may be the same as or different from each other. A is an integer of 0 to 4 and n is a number between 1 and 7)

Epoxy resin used in the present invention in the group consisting of a polyaromatic epoxy resin of the formula (2), biphenyl type, ortho-crasol novolak type, bisphenol F type, bisphenol A type, dicyclopentadiene type of the formula (3) It consists of a single or a mixture of two or more. The polyaromatic epoxy resin of the formula (2) is used in the range of 15 to 75% by weight based on the epoxy resin in the total composition. If the polyaromatic epoxy resin of formula (2) is less than 15% by weight of the epoxy resin, there is a problem of poor flame retardancy, and when it is used more than 75% by weight, there is a problem of poor fluidity. To reduce the productivity.

[Formula 3]

(Wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms)

It is preferable to use the usage-amount of the said epoxy resin in the range of 0.7-14.2 weight% with respect to the whole resin composition.

It is preferable to use a hardening | curing agent in the range of 0.6-10.4 weight% with respect to the whole resin composition. As a curing agent used in the composition of the present invention, a polyaromatic phenol resin having two or more hydroxyl groups represented by the following formula (4) having a hydroxyl equivalent of 100 to 200 is used in an amount of 15 to 70% by weight of the entire phenol resin in the composition. If the multi-aromatic phenolic resin of formula (4) is less than 15% by weight of the entire phenolic resin in the composition, there is a problem that the flame retardancy is poor, when using more than 70% by weight occurs a problem of poor fluidity.

[Formula 4]

(In the above formula, R1 and R2 are alkyl groups having 1 to 4 carbon atoms, which may be the same as or different from each other. Xa is an integer of 0 to 4 and n is a number between 1 and 7).

Along with this, Xyloc resin of Formula 5, a common phenol novolak resin, cresol novolak resin, dicyclopentadiene type alone or two or more in combination with a polyaromatic phenol resin of Formula 4 use.

[Formula 5]

(Wherein, R1 is an alkyl group having 1 to 4 carbon atoms, when a is 2 or more, may be the same or different. A is an integer of 0 to 4, n is a number between 1-7.)

In the present invention, it is more preferable that the equivalent ratio of the epoxy resin and the curing agent is such that the epoxy equivalent to the hydroxyl equivalent is between 0.9 and 1.1 in terms of the degree of curing of the composition, that is, the dimensional stability.

In addition, the adhesive force increasing agent applied to the epoxy resin composition according to the present invention includes a triazine-based resin containing at least one mercapto group terminal group. 예 로서 Detailed examples applied in this patent include 2-dibutylamino-4,6-dimercapto-S-triazine, 2-dibutylamino-mercapto-triazine, 2-anilino-4,6-dimercapto-S- Triazines, 2,4,6-trimercupto-S-triazines can be used as mixtures thereof, and compounds of formula (6) having at least one terminal group in the triazine basic skeleton alone or in combination This was possible. It is preferable to use the said triazine resin at 0.01 to 1.5 weight% with respect to the whole epoxy resin composition.

[Formula 6]

(Wherein R is the same or different mercapto group, alkyl group, or amine group, respectively.)

Meanwhile, in the present invention, as a curing accelerator, a conventional triphenylphosphine may be used, or an isocyanate type latent curing catalyst may be used for controlling the curing rate. Specific examples of the curing accelerators include triazine isocyanate imidazole compounds, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, tetraphenylboron salt and the like as benzyldimethylamine, triethanolamine, Amine compounds such as triethylenediamine, dimethylaminoethanol and tri (dimethylaminomethyl) phenol, and phosphine compounds such as triphenylphosphine, diphenylphosphine and phenylphosphine;

The content of the curing accelerator is preferably used in the range of 0.05 to 0.5% by weight based on the total epoxy resin composition.

In the present invention, the inorganic filler may have an average particle diameter of 0.1 to 35 μm, and fused or synthetic silica in which the content of the particle diameter between 45 to 75 μm is controlled to 0.1 to 50 wt% may be used. 3 to 10% by weight of the whole inorganic filler in the composition of 0.1-2 μm spherical silica, 5 to 20% by weight of the total inorganic filler in the composition of 3-9 μm spherical silica, 10 to 10 20 micrometers of spherical silica is good to mix and use at the ratio of 30 to 92 weight% of the whole inorganic filler in a composition. At this time, the total amount of the inorganic filler in the composition 수 may be applied to 75 to 95% by weight, but preferably 75 to 90% by weight. If the amount of the inorganic filler is less than 75% by weight, sufficient strength and low thermal expansion cannot be realized, and the penetration of moisture is easy, which is fatal to the reliability characteristics. Because there is.

The resin composition of the present invention may be a release agent such as higher fatty acids, natural fatty acids, paraffin waxes, ester waxes, modified silicone oils, and coloring agents such as carbon black and organic / inorganic dyes, as necessary, within the scope of not impairing the object of the present invention. , Crosslinking enhancers, flame retardant aids, leveling agents and the like can be used.

The epoxy resin composition of the present invention is uniformly pulverized by mixing a predetermined amount using a Henschel mixer or Lodige mixer, and after obtaining a primary powder product, melt kneading at about 100 minutes using a roll mill or a kneader within about 10 minutes. After cooling and grinding can be prepared.

One embodiment of the present invention will be described in more detail with reference to the following examples.

Examples and Comparative Examples

According to the mixing ratio as shown in Table 1 by using the above-mentioned components, Examples 1 to 4 and Comparative Examples 1 to 3 were mixed and uniformly pulverized and mixed using a Henschel mixer or a Rödige mixer to form a primary powder. After obtaining the preparation, melt kneading at 100 ° C. within 10 minutes using a roll mill, and then cooled and pulverized to prepare an epoxy encapsulation composition.

Ingredient (Unit; Weight%) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Epoxy Multi-directional Epoxy Resin 6.8 5.8 3.6 3.8 7.4 6.25 3.8 Biphenyl type 4.7 3.6 2.3 2.7 5.1 3.7 2.7 Hardener Multiaromatic Phenolic Resin 5.7 4.1 2.8 2.9 6.4 4.6 3.2 Zylock 3.4 3.1 1.9 2.0 4.7 3.2 2.1 Isocyanate Terminated Polyurethane Prepolymer (Formula 1) 2.0 2.0 1.0 0.2 1.0 0.15 0.1 Triazine resin 0.3 0.3 0.3 0.3 0.3 - - Curing accelerator Triphenylphosphine 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Tetraphenylphosphonium tetraphenylborate 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Inorganic filler Average particle size 1㎛ 8 7 8 8 5 7 8 Average particle size 5㎛ 30 32 35 34 30 33 37 Average particle diameter 18㎛ 38 42 44 45 39 41 42 Flame retardant Brominated Epoxy - - - - - - - Antimony trioxide - - - - - - - Coupling agent γ-glycithoxypropyl n-trimethoxysilane 0.4 0.4 0.4 0.4 0.4 0.4 0.4 coloring agent Carbon black 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Wax Carnauba Wax 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Sum 100 100 100 100 100 100 100

1) Multi-aromatic epoxy resin: NC-3000, Japanese gunpowder
2) Biphenyl type: YX-4000H, JER
3) Multiaromatic Phenolic Resin: MEH-7851, Meiwa
4) Xylock Type: MEH-7800SS, Meiwa
5) Triazine resin: 2-dibutylamino-4,6-dimercapto-S-triazine
6) Brominated epoxy: Bren-S, Japanese gunpowder

The physical properties and the reliability of the epoxy resin composition thus obtained were evaluated and shown in Table 2.

Evaluation item Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Spiral Flow (inch) 57 51 48 41 60 54 46 Glass transition temperature (℃) 128 121 127 120 121 125 127 Adhesion force (kgf) 78 69 72 76 69 42 40 Flexural Strength (kgf / ㎡) 15.7 15.6 17.1 17.0 14.8 15.3 15.1 Flexural modulus (kgf / mm2) 1620 1810 2180 2290 1780 1930 2420 Cracking water After IR-reflow 265 ℃ 0/192 0/192 0/192 0/192 0/192 0/192 0/192 Peeling water IR-reflow 265 ℃ after PCT 24hr 0/192 0/192 0/192 0/192 1/192 7/192 5/192 200 cycle 0/192 0/192 0/192 0/192 2/192 5/192 0/192 500 cycle 0/192 0/192 0/192 0/192 4/192 11/192 6/192

[Property evaluation method]

럴 Spiral Flow

Mold was manufactured based on EMMI standard to evaluate the flow length at molding temperature (175 ℃) and molding pressure 70Kgf / cm2.

㉡ glass transition temperature (Tg), thermal expansion coefficient

Evaluated by TMA (Thermal mechanical Analyser) (Raising temperature 10 ℃ / min)

㉢ Adhesion: Tensile force between the lead frame and epoxy encapsulant (using UTM)

㉣ Flexural strength and modulus: EMC molded specimens (125 X 12.6 X 6.4 mm) cured at room temperature (25 ℃) were prepared, and the width and thickness of the center of the specimen were measured up to 0.001 mm with a micrometer and measured on a UTM tester.

㉤ Crack evaluation

After 28MQFP was molded at 175 ° C for 120 seconds using MPS (Multi Plunger System) molding machine, it was cured after 4 hours at 175 ° C, and then proceeded three times with IR REFLOW temperature at 265 ° C and then using ultrasonic (C-SAM) facility. Evaluate the number of cracks by C-SAM,

㉥ Peelability evaluation

In the Thermal Shock Tester, it was severely tested at 200 and 500 cycles for 10 minutes from -65 ° C to 150 ° C for 10 minutes, respectively, to determine the number of occurrences of more than 10% of peeling between the lead frame and the lead-on chip and the epoxy encapsulant. Evaluate with SAM.

In the embodiment of the present invention, as shown in Table 2, it can be seen that the adhesion properties between the lead-on chip and the lead frame and the epoxy encapsulation material were greatly improved, and showed excellent characteristics in terms of reliability.

As described above, according to the epoxy resin composition for sealing semiconductor elements of the present invention, an isocyanate terminated polyurethane prepolymer, a polyaromatic epoxy resin and a polyaromatic curing agent are used to heat the pad surface and the chip, particularly in a post-semiconductor process. It is possible to provide an epoxy resin composition for sealing a semiconductor element that has improved flame resistance without using a halogen-based flame retardant and a phosphorus-based flame retardant, which are harmful to humans or devices.

In addition, by using a triazine-based resin containing at least one mercapto group as the adhesion increasing agent, the exfoliation problem occurring between the wafer chip surface and the epoxy encapsulant in the semiconductor element encapsulation process can be improved to provide excellent reliability. .

Claims (13)

0.1 to 5% by weight of isocyanate terminated polyurethane prepolymer represented by the following Chemical Formula 1, 0.1 to 10.7% by weight of the polyaromatic epoxy resin represented by the following Chemical Formula 2, 0.1 to 7.3 wt% of the polyaromatic curing agent represented by the following Chemical Formula 4, Epoxy resin composition for semiconductor element sealing, comprising 0.01 to 1.5% by weight of the triazine resin represented by the following formula (6), 0.05 to 0.5% by weight of the curing accelerator, and 75 to 95% by weight of the inorganic filler. [Formula 1]

(Wherein R is a hydrogen atom or a methyl group and n is an integer from 1 to 10). [Formula 2]

(In the formula, R1, R2 is an alkyl group having 1 to 4 carbon atoms. good. a is an integer of 0 to 4 and n is a number between 1 and 7) [Formula 4]

(In the formula, R1, R2 is an alkyl group having 1 to 4 carbon atoms. good. a is an integer of 0 to 4 and n is a number between 1 and 7) [Formula 6]

(Wherein R is the same or different mercapto group, alkyl group, or amine group, respectively.) delete delete delete The method of claim 1, wherein the triazine resin is 2-dibutylamino-4,6-dimercapto-S-triazine, 2-dibutylamino-mercapto-triazine, 2-anilino-4,6- Dimercapto-S-triazine, 2,4,6-trimercupto-S-triazine is at least one selected from the group consisting of epoxy resin composition for sealing semiconductor elements. The method of claim 1, The curing accelerator may be triazine isocyanate imidazole compound, tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, tetraphenylboron salt, benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, tri ( Epoxy resin composition for semiconductor element sealing, characterized in that at least one selected from dimethylaminomethyl) phenol, triphenylphosphine, diphenylphosphine and phenylphosphine. The epoxy resin composition for semiconductor element sealing according to claim 6, wherein the composition uses a isocyanate type latent curing catalyst as a curing accelerator, and further uses an amine type cocatalyst or a phosphine type cocatalyst. The method of claim 1, A semiconductor device further comprising at least one member selected from the group consisting of xyloc resin represented by the following formula (5), a phenol novolak resin, a cresol novolak resin, and a dicyclopentadiene type as a curing agent Epoxy resin composition for sealing. [Formula 5]

(Wherein, R1 is an alkyl group having 1 to 4 carbon atoms, when a is 2 or more, may be the same or different. A is an integer of 0 to 4, n is a number between 1-7.) delete The inorganic filler according to claim 1, wherein the inorganic filler comprises 3 to 10% by weight of the total inorganic filler in the composition of the spherical silica having an average particle diameter of 0.1 to 2 µm, and an inorganic filler in the composition of the spherical silica having an average particle diameter of 3 to 9 µm. Epoxy resin composition for semiconductor element sealing which uses the spherical silica of 5-20 weight% of the whole and 10-20 micrometers of average particle diameters mixedly in the ratio of 70-92 weight% of the whole inorganic filler in a composition. The epoxy resin composition for sealing a semiconductor element according to any one of claims 1 to 10 is mixed using a Henschel mixer or a solid mixer, melt-kneaded with a roll mill or a kneader, and then cooled and pulverized. Semiconductor element sealed with the obtained final powder product. The semiconductor device according to claim 11, wherein the final powder product is sealed by a low pressure transfer molding method, an injection molding method, or a casting molding method. The semiconductor device according to claim 12, wherein the semiconductor device comprises a copper lead frame.