KR20010063329A - Epoxy molding compound for sealing of electronic component - Google Patents

Abstract

PURPOSE: An epoxy resin composition for sealing a semiconductor element is provided which has improved mechanical properties, crack-resistance and flowing property. CONSTITUTION: The epoxy resin composition comprises: (i) 2-10 wt.% of an epoxy resin product which is prepared by pre-treating an ortho cresol epoxy resin with a silane coupling agent having a mercapto group; (ii) 1-8 wt.% of diglycidyl hexamethyl biphenyl epoxy resin; (iii) 0.8-1.2 wt.% of a mixture of a bromic epoxy flame retardant and an antimony trioxide; (iv) 3-7.5 wt.% of a hardener; (v) 0.05-0.40 wt.% of a hardening accelerator; (vi) 77-87 wt.% of an inorganic filler; and (vii) 0.1-0.2 wt.% of wax.

Description

Epoxy resin composition for semiconductor element sealing {EPOXY MOLDING COMPOUND FOR SEALING OF ELECTRONIC COMPONENT}

The present invention relates to a semiconductor device-encapsulated epoxy resin composition having improved reliability by preventing corrosion between the pad surface and the chip even after long-term testing at a high temperature, high pressure, and high humidity under the peeling phenomenon between the wafer chip surface of the semiconductor material and the epoxy sealing material. More specifically, an oxo cresol epoxy resin has a base structure of an epoxy resin preparation pretreated with a silane coupling agent having a mercapto group, a diglycidyl hexamethyl biphenyl, and a mixture of bromine epoxy and antimony trioxide, Phenol Novlac) A curing agent, two or more kinds of latent curing accelerators, waxes, inorganic fillers, characterized in that the epoxy resin composition for sealing semiconductor devices excellent in mechanical and hygroscopic properties and excellent in reliability and molding properties.

In recent years, the degree of integration of semiconductor devices has been improved day by day, and thus the size of wiring elements has been increased, the cell area has been changed in a reduction-oriented manner, and wiring has been multilayered. On the other hand, packages that protect semiconductor devices from the external environment are accelerating their size and thickness from the viewpoint of high-density mounting on a printed board, that is, surface mounting.

As described above, in a resin-sealed semiconductor device in which a large semiconductor device is sealed in a small and thin package, failure frequency is increased due to package crack or aluminum pad corrosion due to thermal stress caused by temperature and humidity changes in the external environment. Accordingly, there is a demand for a high reliability semiconductor device epoxy sealing material through crack resistance and low stress of the epoxy resin package material for sealing. In order to satisfy this, there are methods of reducing moisture absorption, improving adhesive strength and high temperature strength in order to improve crack resistance, controlling fillers in order to reduce stress, lowering thermal expansion coefficient, and elasticity by adding a modifier. The method of reducing is known.

High filling technology due to low stress (high filling due to filler combination) has already been developed, which can suppress package thermal stress. Moreover, in the method of reducing elasticity, the epoxy resin molding material which mix | blended and modified the silicone polymer which was excellent in thermal stability by the modification method (Japanese Patent Laid-Open Nos. 63-1894 and 5-291436) by various rubber components is widely used. It is adopted. Since the silicone oil is incompatible with the epoxy resin, which is the base resin of the molding material, and the curing agent, the silicone oil is in the form of fine particle dispersion (island structure) in the base resin, thereby achieving a low modulus in the state of maintaining heat resistance. However, this technique has a problem in that the adhesion between the lead frame and the epoxy sealant and the lead-on chip and the epoxy sealant is degraded, and when the modifier is introduced, moldability is poor, making it difficult to obtain a highly reliable semiconductor device.

An object of the present invention is to solve the above problems by using an epoxy resin product obtained by pretreatment of an olso cresol epoxy resin with a silane coupling agent having a mercapto group, and adhesive properties between the wafer chip surface and the sealing material, and high temperature, high pressure and humidity for a long time. It is to provide an epoxy resin composition for sealing a semiconductor element having an effect of preventing corrosion of the chip surface even under conditions. In addition, a biphenyl-based epoxy resin is introduced therein to provide an epoxy resin composition for sealing semiconductor devices with improved mechanical properties, crack resistance and flow flowability.

That is, the present invention

(1) 2-10% by weight of an epoxy resin preparation in which an oxo cresol epoxy resin is pretreated with a silane coupling agent having a mercapto group,

(2) 1-8% by weight of diglycidyl hexamethyl biphenyl epoxy resin,

(3) 0.8-1.2 wt% bromine epoxy flame retardant and antimony trioxide mixture,

(4) 3-7.5 weight% of hardeners,

(5) 0.05-0.40 weight% of hardening accelerators,

(6) 77-87 weight% of inorganic fillers,

(7) 0.1-0.2% by weight of wax

It is to provide an epoxy resin composition comprising a.

Hereinafter, the present invention will be described in detail.

In the present invention, the epoxy resin preparation (1) in which the oxo cresol epoxy resin is pretreated with a silane coupling agent having a mercapto group is used for the purpose of improving adhesion characteristics of the semiconductor chip and the resin and preventing the chip from corroding.

The silane coupling agent having a mercapto group used in the preparation of the component (1) is a compound represented by the following formula (4), mercapto methyl trimethoxy silane, mercapto ethyl trimethoxy silane, mercapto ethyl triethoxy silane, mer One or more silanes selected from the group consisting of capto propyl triethoxysilane, mercapto dimethyl dimethoxy silane, phenyl gamma mercapto propyl triethoxy silane can be used.

(Wherein R 'is each independently the same or different methoxy, ethoxy, hydrogen, phenyl group; X is an alkyl group of C _1-8 )

The preferable content ratio of the silane coupling agent with a mercapto group is 2-15 weight% with respect to 100 weight% of epoxy resins used for manufacture of the said component (1). If the content ratio is less than 2% by weight, the effect of improving adhesion properties and reliability is not sufficient, and if the content ratio is more than 15% by weight, it is difficult to solidify after obtaining from the melt master batch which is a pretreatment step.

The oxo cresol epoxy resin used in the preparation of the component (1) is an epoxy resin of the following general formula (1), and may be used by mixing one or more epoxy resins selected from the group consisting of an oxo cresol noblock type biphenyl, dicyclopetadiene, and naphthalene system. have.

(Wherein R is a methyl group or a hydroxy group; G is a glycidyl group)

As described above, the amount of the epoxy resin preparation prepared by the silane treatment is preferably 2-10% by weight of the total resin composition.

The diglycidyl hexamethyl biphenyl epoxy resin (2) used in the present invention is excited by using 2,2 3,3 5,5 hexamethyl 4,4 biphenol (Japanese synthetic rubber) of the following general formula (2) as a starting material. It is a diglycidyl hexa methyl biphenyl epoxy resin of the following formula (3) obtained by putting epichlorohydrin in the ring-opening reaction at a low temperature.

Wherein each R is independently the same or different methyl or hydrogen

The detailed synthesis method is shown in Preparation Example 1, and the physical properties of the resin thus obtained were high purity epoxy resins having an epoxy equivalent weight of 190-230, with a softening point of 70-110 ° C. The diglycidyl hexa methyl biphenyl epoxy resin used in the present invention has a rigid skeleton structure and excellent mechanical strength and shrinkage properties as compared to the conventional biphenyl structure, and thus the incidence of tilt in the assembly process is considerably reduced. The usage-amount is 1-8 weight% of all resin compositions.

In the present invention, the bromine epoxy flame retardant and antimony trioxide mixture 3 is used to impart flame retardancy to the epoxy composition.

The bromine epoxy flame retardant constituting the component (3) is a poly glycidyl ether brominated phenol epoxy having an epoxy equivalent of 250 to 300 and a bromine content of 35 to 40%, and antimony trioxide is mixed and used therein.

In the case of using an excessive amount of bromine and antimony trioxide, there is a problem in that the chip is corroded by impurity ions under high temperature, high pressure, and high humidity to deteriorate the reliability of the semiconductor chip. Therefore, in the present invention, the preferred content of the two components for improving reliability within the range satisfying the specification of flame retardant UL94 V-0 is 0.8-1.2% by weight of the total composition.

The preferred mixing proportion of antimony trioxide to bromine epoxy flame retardant is 20-40% by weight antimony trioxide based on 100% by weight bromine epoxy flame retardant. If antimony trioxide is more than 40% by weight soot is generated a lot of bad marking state in the post-process and adversely affect the reliability, if less than 20% by weight does not meet the flame retardant UL 94 V-0 standard.

In the present invention, the curing agent (4) is a phenol novolak resin, cresol novolak resin, Xylok resin, dicyclopenta having two or more hydroxyl groups and a hydroxyl equivalent weight of 100-200 due to the price and moldability of the epoxy composition. One or more curing agents selected from the group consisting of diene resins can be used. The preferred equivalent ratio of epoxy resin and hardener in component (4) is epoxy equivalent of 0.9-1.1 to hydroxyl equivalent, and the preferred amount of hardener is 3.0-7.5% by weight of the total composition.

In the present invention, the curing accelerator (5) is a material used because the introduction of the component (2) affects the reaction rate as a curing catalyst, and an isocyanate type latent curing catalyst is used to control the curing rate. Specific examples include tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, tetraphenylboron salt, etc., as a triazine isocyanate imidazole compound or triphenyl phosphine addition product of Seecok, Japan. 0.05-0.40 weight% is suitable with respect to the resin composition. In addition, since the latent catalyst alone does not obtain desired curing properties, it is advantageous to use it in combination with other catalysts. As a catalyst which can be used in combination, an amine-based benzyldimethylamine, triethanolamine, triethylenediamine, dimethylaminoethanol, At least one catalyst selected from the group consisting of tri (dimethylaminomethyl) phenol, triphenylphosphine, diphenylphosphine, phenylphosphine.

In the present invention, the inorganic filler (6) preferably uses fused or synthetic silica having an average particle of 0.1-35.0 µm, and a preferable filling amount is 77-87% by weight based on the total composition. If the filling amount is less than 77% by weight, the strength and the effect of preventing thermal expansion cannot be sufficiently realized, and the penetration of moisture becomes easy, which is not critical to reliability, and if it is less than 87% by weight, the flow characteristics are deteriorated and the moldability is not good. .

In the present invention, the wax (7) was used for formability, and higher fatty acids, natural fatty acids, paraffin waxes, ester waxes, and the like were used.

In addition to the above components, carbon black, coloring agents such as organic and inorganic dyes, crosslinking enhancers, flame retardant aids, leveling agents and the like may be used.

The present invention will be described with reference to the following examples, and the following examples are only used to illustrate the present invention, but are not used to limit the protection scope of the present invention.

Example

Preparation Example 1 Preparation of Diglycidyl Hexamethyl Biphenyl Epoxy Resin

0.3 mole of 2,2 '3,3' 5,5 hexamethyl 4,4 'biphenol and 6 moles of epiclohydrin were added to a round-necked flask reaction tube, and 0.01 mole of aqueous tetraammonium chloride solution was added at a reaction temperature of 100 ° C. After slowly reacting in a nitrogen atmosphere for 8 hours, the temperature was lowered to 5 ° C or lower and 50% sodium hydroxide solution was added thereto. At this time, the reaction is carried out for about 4 hours while maintaining the temperature below 5 ℃. The mixed solution of methanol and water was added to the product thus obtained, and the biphenyl epoxy resin used in the present invention was obtained through the purification and drying process through strong stirring.

Preparation Example 2 Preparation of Epoxy Resin by Preprocessing Oxo Cresol Epoxy Resin with Gamma-Coupling Agent

930 g of an oxo cresol noblock type epoxy resin (softening point 65 ° C.) of 193 epoxy equivalents having two or more oxirane groups in a molecule are put in a closed round-neck flask reaction tube and stirred while sufficiently melting at a temperature of 70 to 90 ° C. The desired product was obtained after mixing and stirring the gamma mercapto propyltrimethoxy silane, which is a silane coupling agent having a mercapto group, at a stirring speed of 800-1000 rpm for about 10 minutes.

The epoxy resin composition of the present invention is melt-kneaded the primary powder preparation obtained by uniformly pulverizing the compounding amount of the firing using a Henschel mixer or a Lodige mixer within about 10 minutes at 100 ℃ using a roll mill or a kneader. It is manufactured by cooling and grinding.

The properties and reliability of the epoxy resin composition thus obtained were evaluated by the following method.In order to test the reliability, a thin small outline package type semiconductor device was molded at 175 ° C. for 60 seconds using an MPS (Multi Plunger System) molding machine. The degree of peeling between the lead frame and the lead-on chip and the epoxy sealant was measured using an ultrasonic wave (SAT) facility.

After post-curing at 175 ℃ for 6 hours, the characteristics of the product by harsh testing up to 48 hours, 96 hours, 168 hours, 480 hours, 960 hours in 121 ℃, 2 atm, 100% conditions in the autoclave (PERSS COOKER TEST) device And the degree of corrosion was evaluated.

Examples and comparative examples of the epoxy resin composition are shown in Table 1 and Table 2, respectively, and the results for the general physical properties and the reliability test (peeling) are shown in Tables 2 and 3, respectively.

Example Composition Example 1 Example 2 Example 3 Epoxy | ¹⁾ Mercaptosilane Pretreatment Epoxy Resin | ²⁾ Hexamethylbiphenyl epoxy resin 8.23.7 5.15.2 2.46.0 ³⁾ brominated epoxy resin 0.75 0.80 0.73 Antimony trioxide 0.15 0.20 0.3 ⁴⁾ Xylox Curing Agent - - 4.9 Phenolic Noblec Hardener 6.5 5.04 - Triphenylphosphine 0.07 0.09 0.12 ⁵⁾ latent curing catalyst 0.17 0.12 0.10 Inorganic fillers 80 83 85 Carbon black 0.25 0.25 0.25 Carnauba Wax 0.2 0.2 0.2

(Unit: weight%)

[Remarks]

1) Pretreatment epoxy compound with mercapto propyl trimethoxy silane: Preparation Example 2

2) Hexamethyl biphenyl epoxy: Preparation Example 1

3) Japanese Gunpowder: Bren-s

4) Meiwa: MEH-7800SS

5) 2,4-diamino-6- (2-2-methyl-1-imidazole) ethyl-1,3,5-triazine

Comparative example Composition Example 1 Example 2 Example 3 Epoxy | ¹⁾ Allsocresol Noblock Epoxy Resin | ²⁾ biphenyl epoxy 12- 5.25.0 1.07.6 ³⁾ Brominated epoxy resin 0.7 0.6 0.90 Antimony trioxide 1.0 0.1 0.20 Phenolic Novolac Curing Agent 5.3 5.1 - Xyloc Curing Agent - - 4.3 Triphenylphosphine 0.15 0.15 0.15 Inorganic fillers 80 83 85 ⁴⁾ -glycithoxypropyltrimethoxysilane 0.40 0.40 0.40 Carbon black 0.25 0.25 0.25 Carnauba Wax 0.20 0.20 0.20

(Unit: weight%)

[Remarks]

1) Nippon kayaku: EOCN 1020-55

2) Yuka shell: YX-4000 H

3) Japanese Gunpowder: ESB-400T

4) UCC: Silan A-187

General physical properties Evaluation item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Spiral Flow (inch) 35 34 32 36 34 35 Glass transition temperature Tg (℃) 157 139 132 167 142 128 Thermal expansion coefficient 1 (/ m, ℃) 11.2 10.8 10.2 11.3 11.0 10.3 Adhesion (Kgf) 80 76 68 42 49 50 Flame Retardant (UL V-O 1.6mm) V-0 V-0 V-0 V-0 V-1 V-0

Reliability evaluation Evaluation Item Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Peeling Evaluation Preconditioning 0/128 0/128 0/128 31/128 6/128 1/128 After precondition 0/128 0/128 0/128 128/128 19/128 7/128 PCT 48 hours later 0/100 0/100 0/100 0/100 0/100 0/100 96 hours later 0/100 0/100 0/100 12/100 0/100 0/100 In 168 hours 0/100 0/100 0/100 58/100 0/100 16/100 After 480 hours 0/100 0/100 0/100 - 18/100 76/100 After 720 hours 0/100 0/100 0/100 - 62/100 - Remarks No corrosion Poor characteristics due to corrosion

(Defective / Total Test Samples)

[Property evaluation method]

* Spiral Flow

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

Gel Time

Measure the time from melting the epoxy sealant powder on the 175 ℃ hot plate to gelation

* Glass transition temperature (Tg), thermal expansion coefficient

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

* Attachment force: Tensile force between lead frame (alloy 42) and epoxy sealant (using UTM)

* Peel rating

Evaluation of the interface between a wafer chip (LOC: lead-on chip) and an epoxy sealing material (number of semiconductor devices generated / number of semiconductor devices tested); Evaluated with SAT facilities

Before preconditioning conditions: Evaluate the thermal shock test without proceeding.

After preconditioning condition: evaluation after thermal shock test

* PRESS COOKER TEST

Characterization of final product and evaluation of chip corrosion after 168 hours at 121 ℃ 2atm 100% condition

* Flame retardant: UL 94 vertical test based on 1 / 16inch.

5 tests of sparking the flame for 10 seconds after the flame has gone out

Flame retardancy test 1st and 2nd combustion time Sum of secondary burning time and glowing time for each specimen Total time of primary and secondary combustion time of 5 specimens V-0 Within 10 seconds Within 30 seconds Within 50 seconds V-1 Within 30 seconds Within 60 seconds Within 250 seconds V-2 Within 30 seconds Within 60 seconds Within 250 seconds

As shown in Table 3 and Table 4, the epoxy resin composition according to the present invention was found to have significantly improved the adhesion properties between the lead-on chip and the lead frame and the epoxy sealant, and showed excellent characteristics in terms of reliability.

As confirmed through the results of Table 1, Table 3 and Table 4, the epoxy resin composition of the present invention is a pre-treated epoxy preparation and diglycidyl hexamethyl biphenyl with a mercapto silane coupling agent as a basic epoxy resin By applying mechanical properties, resin adhesion and other physical properties are improved to have the advantage of excellent reliability.

Claims (5)

(1) 2-10% by weight of an epoxy resin preparation in which an oxo cresol epoxy resin is pretreated with a silane coupling agent having a mercapto group, (2) 1-8% by weight of diglycidyl hexamethyl biphenyl epoxy resin, (3) 0.8-1.2 wt% bromine epoxy flame retardant and antimony trioxide mixture, (4) 3-7.5 weight% of hardeners, (5) 0.05-0.40 weight% of hardening accelerators, (6) 77-87 weight% of inorganic fillers, (7) 0.1-0.2% by weight of wax An epoxy resin composition comprising a. 3. The epoxy resin composition according to claim 2, wherein the silane coupling agent having a mercapto group used to pretreat the component (1) is gamma-mercaptopropyl methoxy silane of the following formula (4). [Formula 4] (Wherein R 'is each independently the same or different methoxy, ethoxy, hydrogen, phenyl group; X is an alkyl group of C _1-8 ) The epoxy resin composition according to claim 1, wherein the component (2) is a compound represented by the following general formula (2). [Formula 3] The epoxy resin composition according to claim 1, wherein the proportion of bromine epoxy flame retardant and antimony trioxide constituting the component (3) is 20-40% by weight antimony based on 100% by weight bromine epoxy flame retardant. The isocyanate type latent curing accelerator according to claim 1, wherein the component (5) is selected from the group consisting of tetraphenylphosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, and tetraphenylboron salt. Epoxy used for use with at least one catalyst selected from the group consisting of triethanolamine, triethylenediamine, dimethylaminoethanol, tri (dimethylaminomethyl) phenol, triphenylphosphine, diphenylphosphine, phenylphosphine Resin composition.