KR20050071166A - Epoxy resin composition for sealing semiconductor element - Google Patents

Abstract

The present invention relates to an epoxy resin composition for encapsulating a semiconductor device, and more specifically, 5 to 10% by weight of an epoxy resin, 3 to 10% by weight of a curing agent including an organic flame retardant represented by Formula 1, and an inorganic containing an inorganic flame retardant. 75 to 90% by weight of a filler and other additives, wherein the organic flame retardant comprises 50 to 90% by weight relative to the total curing agent, and the inorganic flame retardant is selected from at least one of Group IIA, IIB, IIIB and VIA metal elements and averages The present invention relates to an epoxy resin composition for encapsulating a semiconductor device having a particle size of 0.2 to 5.0 μm.

Formula 1

The resin composition for encapsulating semiconductor devices according to the present invention has an environmentally friendly advantage because it has flame retardancy without impairing moldability by filling inorganic and organic materials.

Description

Epoxy resin composition for sealing semiconductor element

The present invention relates to an epoxy resin composition for encapsulating a semiconductor device, and more particularly, by filling an inorganic flame retardant and an organic flame retardant containing a certain amount of nitrogen without using a toxic flame retardant such as bromine or antimony, the formability is not impaired. The present invention relates to an epoxy resin composition for encapsulating a semiconductor device that is flame-retardant and environmentally friendly.

In the past, brominated epoxy resins and antimony trioxide were used as a flame retardant in epoxy resin compositions for semiconductor device encapsulation because they can secure stable flame retardancy even in a small amount. However, the environmental hazards of bromine and antimony are regulated to be regulated. There is an active movement to develop alternative flame retardant technology that does not use antimony.

In general, flame retardants can be classified into additive and reactive forms. The addition type is a type that is mixed and dispersed in a resin composition, and the reaction type is a type that reacts chemically with a functional group in a molecule such as a brominated epoxy resin.

Additional types include organic flame retardants and inorganic flame retardants. Organic flame retardants include phosphorus, nitrogen, and halogens. However, phosphorus and halogens are harmful to humans. Inorganic flame retardants include boron compounds, antimony trioxide, aluminum hydroxide, VIA metals, and Zn, which is a group IIB, but antimony trioxide is harmful to humans and its use is limited and other inorganic flame retardants have been widely considered. In particular, when the inorganic flame retardant is a powder type, the problem of particle diameter is very important. While maintaining the average particle diameter and particle size distribution in consideration of the reinforcement of the polymer, the smaller particle diameter increases the surface area and increases the chance of reaction, thereby increasing the flame retardant effect. Looking at the related art, when securing the flame retardancy by increasing the inorganic filler content of the composition there is a possibility that a variety of problems, such as poor continuous workability when applying the semiconductor process due to the viscosity of the composition increases. On the other hand, when a nitrogen-based flame retardant is used alone, an excessive amount is used to obtain the desired flame retardancy, and as the nitrogen content is increased, it affects the curing behavior of the epoxy resin encapsulant, thereby degrading moldability.

Therefore, in the present invention, as a result of the research to solve the above problems, by using a mixture of an organic flame retardant and an inorganic flame retardant containing a certain amount of nitrogen can ensure flame retardancy without impairing workability, and improve the reliability An epoxy resin composition for sealing a semiconductor device was obtained, and the present invention was completed based on this.

Accordingly, an object of the present invention is to provide an epoxy resin composition for encapsulating a semiconductor device having high flame retardancy without using bromine and antimony by using an inorganic flame retardant and an organic flame retardant, and having no problem in workability and having excellent reliability.

The epoxy resin composition for encapsulating a semiconductor device of the present invention for achieving the object of the present invention is 5 to 10% by weight epoxy resin, 3 to 10% by weight of a curing agent containing an organic flame retardant represented by the formula (1), including an inorganic flame retardant Including 75 to 90% by weight of inorganic filler and other additives, the organic flame retardant is included in the 40% by weight or more based on the total curing agent, preferably 50 to 90% by weight is advantageous to obtain high reliability. The inorganic flame retardant is at least one selected from Group IIA, IIB, IIIB and VIA metal elements and has an average particle size of 0.2 to 5.0 μm.

Formula 1

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

As mentioned above, the epoxy resin composition of the present invention includes an epoxy resin, a curing agent, an inorganic filler, and other additives.

The epoxy resin used in the present invention may be used by mixing one or two or more from ortho cresol novolak type, biphenyl type, bisphenol A type, polyfunctional type, naphthalene type, and dicyclopentadiene type epoxy resin. The amount thereof is preferably 5 to 10% by weight.

The curing agent is used by mixing one or two or more from a nitrogen-containing organic flame retardant represented by the following formula (1) and a novolak type, xylox type, polyfunctional type, naphthalene type, and dicyclopentadiene type phenol resin. The nitrogen-containing organic flame retardant is particularly preferably a melamine-modified phenol novolak resin. In the chemical structure of melamine, the bond is harder than the carbon-only structure, which is more effective in suppressing the radical reaction during combustion. In addition, since the curing behavior may vary depending on the nitrogen content contained, use a nitrogen content of 5 to 20% by weight.

The amount of the total curing agent is preferably 3 to 10% by weight, the organic flame retardant represented by the following formula (1) is applied to 40% or more by weight of the total curing agent content, using 50 to 90% by weight to ensure flame retardancy and high reliability It is desirable to achieve. When the content of the organic flame retardant represented by the following Chemical Formula 1 is less than 50% by weight of the total curing agent, it is difficult to secure flame retardancy, and when the content of the organic flame retardant exceeds 90% by weight, the curing rate of the cured product is excessively shortened.

In the present invention, the equivalent ratio of the curing agent to 1 equivalent of the epoxy resin is 0.6 to 1.4, preferably 0.8 to 1.2.

Here, R <_1> is a C1-C4 hydrocarbon group, R <_2> is a C1-C10 hydrocarbon group, m is an integer of 2-10, n is an integer of 1-10.

On the other hand, the inorganic filler used in the present invention includes an inorganic flame retardant, high purity natural silica, synthetic silica, molten silica or alumina is used together, the properties thereof can be applied to both spherical and each phase. For the flame retardancy, the total amount of the inorganic filler used is 70 to 95% by weight, preferably 75 to 90% by weight.

In the case of the inorganic flame retardant, it is necessary to observe the pyrolysis behavior and select it. In particular, inorganic flame retardants containing crystal water such as magnesium and aluminum show endothermic peaks due to dehydration reaction at a constant temperature.As the endothermic amount is higher, the flame retardant effect is increased, but the reliability reduction due to dehydration should also be considered. . In order to increase the flame retardant effect, increase the amount of inorganic flame retardant, and improve the mechanical properties, the surface treatment technology has been studied, the surface treatment type by stearic acid or silane coupling agent is a trend that is used as a general type. In the case of magnesium hydroxide, the pyrolysis temperature is a representative flame retardant at high temperatures. It exhibits a flame retardant effect by the endothermic reaction at 340 to 490 ° C. Aluminum hydroxide has a disadvantage in that the dehydration start temperature is low, so it is better not to use an excessive amount so as not to impair reliability. If the processing temperature is low, it can be used stably. Mineral flame retardants have different characteristics for each mineral. It has different properties such as the effect of suppressing the rise of material temperature, the effect of lowering the amount of heat dissipation, the increase of the ignition point, the extension of the ignition time, the increase of the oxygen index, the effect of promoting carbonization, etc. Should be considered.

In the present invention, a transition metal complex having an average particle size of 0.5 to 5.0 mu m is used, in particular selected from Group IIA, IIB, IIIB and VIA elements. In particular, one or more may be selected from Mg of Group IIA, Zn of Ca IIB, Mo, W of Group B, Al, Ti, and VIA of Group IIIB, or may be used by mixing one or three of the above elements with another metal. have.

The amount of the inorganic flame retardant is preferably 5 to 30% of the total ash weight when the total ash weight of the semiconductor element epoxy encapsulant is 70 to 90%.

In addition, the composition of the present invention may further include additives such as colorants, flame retardants, curing accelerator release agents, coupling agents, and modifiers generally applied as an optional component, wherein the curing accelerator is 0.1 to 1.0% by weight, colorant Is 0.1 to 1.0% by weight, and other additives may be included in an amount of 1 to 5% by weight.

The epoxy resin composition for encapsulation of the semiconductor device of the present invention is mixed with each raw material as described above and melt mixed at a temperature of 100 ℃ to 130 ℃ using a melt mixer (Kneader) to cool to room temperature and pulverized to a powder state and blended It may be prepared by a general manufacturing method through the process.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited thereto.

Examples 1-2

As the epoxy resin, a resin of formula 2 (epoxy equivalent = 184 g / eq.) And a resin of formula 3 (epoxy equivalent = 195 g / eq.) Were used, and a curing agent of formula 4 (hydroxyl equivalent = 175 g / eq.) And A resin of formula 5 (hydroxyl equivalent = 107 g / eq.) Was used. In addition, zinc molybolate and magnesium hydroxide complex are used as inorganic flame retardants, and the resin of Chemical Formula 1a is measured as shown in Table 1 as an organic flame retardant and mixed with other constituent raw materials. Melt mixing, cooling, grinding and blending were performed.

Comparative Examples 1 to 3

As the epoxy resin, a resin of formula (2) (epoxy equivalent = 184 g / eq.) And a resin of formula (3) (epoxy equivalent = 195 g / eq.) Were used. As a curing agent, a resin of formula (4) (hydroxyl equivalent = 175 g / eq.). ) And a resin of Formula 5 (hydroxyl equivalent = 107 g / eq.) Were used, and the inorganic flame retardant was weighed as in Table 2, and the same procedure as in Example was performed.

In particular, Comparative Examples 2 and 3 were compared with Examples using conventional halogen-based flame retardant resins and flame retardants. A brominated epoxy resin was used as the halogen flame retardant resin, and antimony trioxide was used as the halogen flame retardant.

Where m is 2 and n is 1.

In the case of Formula 1a, it is a curing agent and an organic flame retardant. The compound of Formula 1a used in the present invention has a hydroxyl equivalent of 140 g / eq, a softening point of 82 ° C., and a viscosity of about 2.5 poise at 150 ° C. The nitrogen content is 18%, which is manufactured by Gun-EI.

Where n is 1.

Where n is 1.

Where n is 1.

Using the epoxy resin composition prepared as described above was measured the flow (Spiral Flow) in a heat transfer molding machine (pressure = 70kg / ㎠, temperature = 175 ℃, curing time = 120 seconds), to prepare a test piece for flame retardancy measurement. In order to fabricate flame retardant specimens, the flow measurement results should be at least 20 inches.

Flame-retardant test specimens are post-cured at 175 ℃ for 6 hours and the flame retardancy is measured in Table 2 below.

The lead frame and adhesion were evaluated as a method to verify the reliability improvement. The enhanced adhesion reduces the delamination between the interfaces within the package, which is advantageous for reliability.

division unit Example One 2 Epoxy Formula 2 weight% 7.44 - Formula 3 weight% - 8.50 Hardener Formula 4 weight% 3.71 - Formula 5 weight% - 2.44 Formula 1a weight% 2.97 3.19 Inorganic flame retardants weight% 5 5 Coupling agent weight% 0.48 0.48 Silica weight% 80.0 80.0 additive weight% 0.18 0.18 coloring agent weight% 0.22 0.22 Curing accelerator weight% 0.24 0.24 Flow assessment liquidity inch 25 60 Curing time second 23 29 Flame Retardant Rating UI94 test V0 V0 Total flame time second 16 23

division unit Comparative example One 2 3 Epoxy Formula 2 weight% 6.54 9.47 9.47 Formula 3 weight% - - - Hardener Formula 4 weight% 7.04 4.65 4.65 Formula 5 weight% - - - Inorganic flame retardants weight% - 5 15 Brominated epoxy weight% 0.54 - - Sb ₂ 0 ₃ weight% 1.2 - - Coupling agent weight% 0.48 0.48 0.48 Silica weight% 83.8 80.0 70.0 additive weight% 0.18 0.18 0.18 coloring agent weight% 0.22 0.22 0.22 Curing accelerator weight% 0.24 0.24 0.24 Flow assessment liquidity inch 27 29 31 Curing time second 29 30 31 Flame Retardant Rating UL94 test V1 failure failure Total flame time second 128 - -

division Adhesion test Example Comparative example One 2 One 2 3 Mpa 63.11 61.25 45.32 52.35 53.24 Workability and Reliability Assessment Void (a) 0/50 0/50 2/50 1/50 3/50 Peel off top (ea) 2/50 3/50 7/50 13/50 15/50 Peeling bottom (ea) 1/50 2/50 7/50 11/50 12/50 Crack (ea) 0/50 0/50 2/50 1/50 3/50 Reliability level Pass Level 2a Pass Level 2a Level 2a failed Level 2a failed Level 2a failed

The measurement method for each property is as follows.

* Flame Retardant (UL94V) Rating

Specimens 125 mm long, 13 mm wide, and 3 mm thick were prepared and measured by UL94 vertical flame retardant test. The distance between the end of the specimen and the bottom is 30 cm, and the distance between the burner and the specimen is at least 150 mm. It is shown in Table 4 in detail.

Reference conditions V-0 V-1 V-2 T1 to t2 respectively ≤10 seconds ≤30 seconds ≤30 seconds ∑ (t1 + t2) ≤50 seconds ≤250 seconds ≤250 seconds Each (t2 + t3) ≤30 seconds ≤60 seconds ≤60 seconds After flame or incandescence of specimen to holding clamp none none none Cotton marker burned by flame particles or drops none none has exist

* Adhesive force measurement

In order to fabricate the specimen as shown in Figure 1 using a copper frame and a mold using a heat transfer molding machine (pressure = 70kg / ㎠, temperature = 175 ℃, curing time = 120 seconds) and then molded for 6 hours in an oven at 175 ℃ Post-curing, and then subjected to tension in the direction shown in Figure 2 with a universal testing machine (UTM) before and after 48 hours at 85 ° C./85%RH conditions to reduce the load at the point where the copper frame falls from the epoxy resin composition. It measures and converts into adhesive force value (MPa). It is shown in Table 3 above.

* Liquidity measurement

Using a flowable mold of the EMMI-I-66 standard, it is measured by a heat transfer molding machine (pressure = 70kg / cm 2, temperature = 175 ° C, curing time = 120 seconds). It is shown in Tables 1 and 2, respectively.

* Measurement of curing time

After the epoxy resin cured product for semiconductor encapsulation was applied to the hot plate thinly, the time from the time of application to the time of hardening was measured by a stopwatch. At this time, the temperature of the hot plate is 175 ℃. It is shown in Tables 1 and 2, respectively.

* Pore measurement

After molding in 50 cavities in the LQFP package (body size: 20 mm × 20 mm, 144 lead) molds, the number of cavities in which the voids were formed is shown in Table 3 above.

* JEDEC reliability evaluation and peeling measurement

Molded in a heat transfer molding machine (pressure = 70kg / ㎠, temperature = 175 ℃, curing time = 120 seconds) using an LQFP package (body size: 20mm × 20mm, 144 lead) mold with SiN chip attached, and then 60 ℃. After absorbing for 40 hours at a relative humidity of 60%, IR-reflow was applied at a maximum temperature of 240 ° C. and then applied three times. Using ultrasonic flaw detector (SAT), peeling of package pad part, ie, interface between encapsulant and upper pad and SiN chip surface, and the number of interfacial peeling between encapsulant and lower lead frame and existence of cracks are checked. Will pass through. The degree of peeling was expressed as the number of peelings occurring in 50 units of sealed packages. Table 5 shows JEDEC reliability determination standards. Passing Level 3 progressed to Level 2a assessments, while passing Level 3 progressed further to Level 2 assessments. The reliability determination results are shown in Table 3 above.

 * JEDEC STANDARD level Hours Condition 2 168 85 ℃ / 60% / RH  2a 120 60 ℃ / 60% / RH 3 40 60 ℃ / 60% / RH

As can be seen from the above examples and comparative examples, when the resin composition of the present invention is encapsulated by using an organic flame retardant and an inorganic flame retardant, the workability does not decrease, and the flame retardancy of UL94 V-0 is ensured, and the adhesive force There is an advantage that the promotion and reliability of the package is improved.

1 shows schematically a device for testing the adhesion of a composition according to the invention.

※ Explanation of code about main part of drawing ※

1: epoxy resin composition 2: copper frame

←, →: direction in which tension is applied

Claims (3)

5 to 10% by weight of epoxy resin, 3 to 10% by weight of a curing agent comprising an organic flame retardant represented by Formula 1, 75 to 90% by weight of an inorganic filler including an inorganic flame retardant and other additives, wherein the organic flame retardant is a total curing agent 50 to 90% by weight of the inorganic flame retardant is selected from at least one of the group IIA, IIB, IIIB and VIA metal elements, and the epoxy resin composition for semiconductor element encapsulation, characterized in that the average particle size is 0.2 to 5.0㎛ ; Formula 1 Here, R <_1> is a C1-C4 hydrocarbon group, R <_2> is a C1-C10 hydrocarbon group, m is an integer of 2-10, n is an integer of 1-10. The epoxy resin composition for encapsulating a semiconductor device according to claim 1, wherein the organic flame retardant has a nitrogen content of 5 to 20 wt%. The method of claim 1, wherein the inorganic flame retardant is selected from the group consisting of Mg of Group IIA, Zn of Ca IIB group, B, Al, Ti of Group IIIB, Mo, W of Group VIA and W, Epoxy resin composition.