KR102772596B1 - Underfill Adhesive Composition - Google Patents

Abstract

The present invention relates to an underfill adhesive composition comprising: 13 to 21 wt% of a first epoxy resin; 5 to 15 wt% of a second epoxy resin; 2 to 10 wt% of a latent curing agent; 24 to 48 wt% of a micro-spherical silica filler; 12 to 36 wt% of a nano-spherical silica filler; 0.05 to 0.5 wt% of a stabilizer; 0.5 to 5.0 wt% of a wetting and dispersing agent; 0.1 to 1.0 wt% of a silane coupling agent; and 0.1 to 1.0 wt% of a defoaming agent.

Description

{Underfill Adhesive Composition}

The present invention relates to an underfill adhesive, and more particularly, to an underfill adhesive composition comprising a powder spherical silica filler and additionally a core shell rubber (CSR) resin.

Underfill adhesives can be classified into wire bonding, flip chip bonding, etc. Wire bonding has various inefficient problems, so the flip chip bonding method is used to overcome these problems. The flip chip bonding method is a method in which a chip with solder balls or bumps formed is flipped over and mounted so that the flip surface faces the substrate (Korean Patent Publication No. 10-2009-0106784). This is a method that can implement the smallest form among semiconductor packaging.

In the above flip chip process, there is a problem that the bonding reliability between the solder bump and the pad becomes weak. To solve this problem, an underfill epoxy resin is used in the space between the substrate and the chip to supplement the bonding reliability problem.

Flip chip underfill contains filler, which has the function of reducing mechanical stress by lowering the coefficient of thermal expansion (CTE) of the material and thus reducing the CTE mismatch between the substrate and the chip, and therefore must be used.

In order to improve the moisture resistance and heat cycle resistance of a portion sealed with a liquid encapsulating agent, it is known that a method of controlling the difference in thermal expansion coefficient between a substrate and a semiconductor element by adding a filler made of an inorganic material such as a silica filler to the liquid encapsulating agent and reinforcing a bump electrode is effective (Japanese Patent Laid-Open No. 10-1731103).

In flip-chip semiconductor devices, low thermal expansion (CTE (Coefficient of Thermal Expansion)) is required to prevent miniaturization of the Low-K layer, lead-free solder bumps, destruction of the Low-K layer due to thermal stress, and cracking of solder bumps.

In order to lower the CTE (Coefficient of Thermal Expansion) of a liquid encapsulating material, it is essential to increase the filling rate of the filler (increase the filling rate of the filler). However, as the filling rate of the filler increases, the viscosity also increases, which reduces the injectability into the gap between the semiconductor element and the substrate.

Meanwhile, as the filling ratio of the filler increases, the brittle property increases, and as the brittle property increases, the fracture toughness decreases. In addition, although the thermal stress is alleviated as the filling ratio of the filler increases, the stress of the adhesive composition itself is not alleviated.

If the stress of the adhesive composition itself is not relieved, cracks will occur in the adhesive composition itself, and a thermoplastic resin for modification must be used to supplement the brittle nature and stress of the adhesive composition itself.

(0001) Republic of Korea Publication Patent No. 10-2015-0023560 (0002) Republic of Korea Publication Patent No. 10-2022-0062762

The present invention is intended to solve the problems of the prior art, and to reduce thermal stress between the substrate and the chip, and to realize workability and injectability at the same time by lowering the coefficient of thermal expansion (CTE) by increasing the filling rate of the filler while maintaining low viscosity and low thixotropy so that the injectability between the semiconductor element and the substrate is not reduced, and to prevent the occurrence of solder bump cracks due to thermal stress.

In addition, the present invention aims to prevent cracks from occurring in the adhesive composition itself by using the brittle nature of the adhesive itself due to an increase in the filling ratio of the filler and the effect of relieving the stress of the adhesive composition itself.

In order to solve the above problems, the present invention provides an underfill adhesive composition comprising: 13 to 21 wt% of a first epoxy resin; 5 to 15 wt% of a second epoxy resin; 2 to 10 wt% of a latent curing agent; 24 to 48 wt% of a micro-spherical silica filler; 12 to 36 wt% of a nano-spherical silica filler; 0.05 to 0.5 wt% of a stabilizer; 0.5 to 5.0 wt% of a wetting and dispersing agent; 0.1 to 1.0 wt% of a silane coupling agent; and 0.1 to 1.0 wt% of an antifoaming agent.

In addition, the present invention provides an underfill adhesive composition further comprising 5 to 15 wt% of a thermoplastic resin for modification in addition to the above underfill adhesive composition.

In addition, the present invention provides an underfill adhesive composition, wherein the first epoxy resin has an epoxy equivalent of 155 to 160 g/eq, a viscosity of 1,000 to 2,000 cps, and is a bifunctional bisphenol F type.

In addition, the present invention provides an underfill adhesive composition, wherein the second epoxy resin has an epoxy equivalent of 120 to 140 g/eq, a viscosity of 300 to 1,000 cps, and is a bifunctional resorcinol diglycidyl ether.

In addition, the present invention provides an underfill adhesive composition characterized in that the latent curing agent is solid at 20 to 25°C and is a modified aliphatic polyamine.

In addition, the present invention provides an underfill adhesive composition characterized in that the micro spherical silica filler has a particle diameter of 1 to 30 um and a specific surface area of 1.0 to 5.0 m2/g.

In addition, the present invention provides an underfill adhesive composition characterized in that the nano spherical silica filler has a particle diameter of 100 to 900 nm and a specific surface area of 5 to 30 m2/g.

In addition, the present invention provides an underfill adhesive composition characterized in that the stabilizer is at least one of barybuturic acid, a boric acid ester compound, aluminum, and a chelate.

In addition, the present invention provides an underfill adhesive composition characterized in that the wetting and dispersing agent has a solid content (NON-VOLATILE MATTER) of 99% or more.

In addition, the present invention provides an underfill adhesive composition characterized in that the silane coupling agent is a mixture of at least one of a vinyl group, an epoxy group, an amino group, and an acryloxy group.

In addition, the present invention provides an underfill adhesive composition characterized in that the thermoplastic resin for modification is a core shell rubber (CSR) having a viscosity of 5,000 to 8,000 cps and a particle size of 50 to 150 nm.

The adhesive composition of the present invention can improve workability and injection property by maintaining low viscosity and low thixotropy by using fine powder spherical silica filler, and can prevent solder bump cracking by reducing thermal stress between a substrate and a chip by lowering the coefficient of thermal expansion (CTE) by increasing the filling ratio of the filler.

In addition, the present invention uses core shell rubber (CSR) as a thermoplastic resin for modification to alleviate the brittle nature and fracture toughness of the adhesive composition itself due to an increase in the filling ratio of the filler, and can prevent the occurrence of cracks in the adhesive composition itself due to the effect of alleviating the stress of the adhesive composition itself.

Hereinafter, a preferred embodiment of the present invention will be described in detail. First, in describing the present invention, a specific description of related known functions or configurations is omitted in order to avoid obscuring the gist of the present invention.

The terms “about,” “substantially,” and the like used in this specification are used in a meaning that is at or close to the numerical value when manufacturing and material tolerances inherent in the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly utilizing the disclosure in which exact or absolute numerical values are mentioned to aid understanding of the present invention.

The underfill adhesive composition of the present invention is characterized by containing: 13 to 21 wt% of a first epoxy resin; 5 to 15 wt% of a second epoxy resin; 2 to 10 wt% of a latent curing agent; 24 to 48 wt% of a micro-spherical silica filler; 12 to 36 wt% of a nano-spherical silica filler; 0.05 to 0.5 wt% of a stabilizer; 0.5 to 5.0 wt% of a wetting and dispersing agent; 0.1 to 1.0 wt% of a silane coupling agent; and 0.1 to 1.0 wt% of a defoaming agent.

This also applies to those containing an additional 5 to 15 wt% of a thermoplastic resin for modification.

The above composition is described in detail below.

1. First epoxy resin

The first epoxy resin may be a single type of resin, such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, amino epoxy resin, or alicyclic epoxy resin, or two or more types may be used in combination.

Bisphenol A type epoxy resin is preferably one having an epoxy equivalent of 150 to 400 g/eq, and examples of commercially available products include YD-128, YD-134, YD-136, KDS-8128, YD-113, YD-114, YD-127, YD-115 all from KUKDO Chemical, EP-4300E, EP-4000S, EP-4010S all from ADEKA, EPICLON 840, EPICLON 850 all from DIC, EPON825, EPON826, EPON828, EPON830 all from Huntsman, and EPALLOY-7192 all from Trahem.

Bisphenol F type epoxy resins are preferably those having an epoxy equivalent of 150 to 400 g/eq, and examples of commercially available products include YDF-165, YDF-170, YDF-1020, KDS-8170, YDF-151, YDF-175, YDF-2001, YDF-2004 from Kukdo Chemical, EP-4901E from ADEKA, EPICLON 830, EPICLON 830-S, EPICLON 835, EPICLON 835LV from DIC, and DER354 from Dow Chemical. Preferably, they are difunctional bisphenol F type and have the characteristics of an epoxy equivalent of 155 to 160 g/eq and a viscosity of 1,000 to 2,000 cps.

Novolac resins include phenol novolac resins and cresol novolac resins. Phenol novolac epoxy, a phenol analogue, is preferably used with an equivalent weight of 160 to 200 g/eq, and examples of commercially available products include YDPN-628, YDPN-631, YDPN-638 from Kukdo Chemical, and EPICLON N-740, EPICLON N-770, EPICLON N-775, EPICLON N-865 from DIC.

The phenol novolac epoxy, which is a cresol analogue, preferably has an equivalent weight of 190 to 220 g/eq, and examples of commercially available products include YDCN-500-1P, YDCN-500-4P, YDCN-500-5P, YDCN-500-7P, YDCN-500-8P, YDCN-500-10P from Kukdo Chemical, and EPICLON N-660, EPICLON N-665, EPICLON N-670, EPICLON N-673, EPICLON N-680, EPICLON N-695 from DIC.

In addition, for amino epoxy, the epoxy equivalent is 95g/eq, and there are ADEKA's EP-3950S and EP-3950L, etc.

Alicyclic epoxy resins have an epoxy equivalent of 120 to 220 g/eq, and include CELLOXIDE 2021P, CELLOXIDE 2081, CELLOXIDE 2000, EHPE 3150, EPOLEAD GT401 from DAICEL, and EPALLOY-5000 and EPALLOY-5200 from TRAHEM.

2. Second epoxy resin

The second epoxy resin may be a single resin, such as a resorcinol epoxy resin or a modified phenol novolac resorcinol epoxy resin, or may be used in combination of two or more types.

Preferably, it is a bifunctional resorcinol diglycidyl ether, and examples of commercially available products having an epoxy equivalent of 120 to 140 g/eq and a viscosity of 300 to 1,000 cps include TRD-130 and SEV-5765 from SHIN-A.

The modified phenol novolac resorcinol epoxy resin preferably has an epoxy equivalent of 120 to 170 g/eq, and examples of commercially available products include ERISYS-RF50, ERISYS-RN25, and ERISYS-RN3650 from TRAHEM.

3. Potential hardener

Latent curing agents are compounds that are solid at room temperature and become activated when heated. Representative examples include reaction products of amine compounds or imidazole compounds with epoxy compounds.

Specific examples of imidazole compounds which are solid at room temperature and examples of commercially available products include 2-methyl imidazole (2-MZ-H), 2-undecyl imidazole (C11Z), 2-heptadecyl imidazole (C17Z), 2-ethyl-4-methyl imidazole (2E4MZ), 2-phenyl imidazole (2PZ, 2PZ-PW), 2-phenyl-4-methyl imidazole (2P4MZ), 1-benzyl-2-methyl imidazole (1B2MZ), 1-benzyl-2-phenyl imidazole (1B2PZ), 1H imidazole (SIZ), P-0505 from SHIKOKU, FXR-1020 from FUJI, and EH-5011S from ADEKA.

Examples of commercially available products which are modified aliphatic polyamines which are reaction products of amine compounds and epoxy compounds include FXR-1081, FXR-1030 from FUJI, PN-23, PN-H, PN-31, PN-40, PN-23J, PN-31J, PN-40J, MY-23, MY-24, MY-H, MY-HK from AJINOMOTO INC., and EH-3731S, EH-4360S, EH-4370S, EH-4357S from ADEKA.

4. Micro spherical silica filler

Commercially available micro-spherical silica fillers include FB-7SDC, FB-5SDC, FB-3SDC, FB-7SDX, FB-5SDX, FB-3SDX, FB-302X, FB-100X, FB-105X, FB-940X, FB-945X, FB-950X from DENKA, SO-C4, SO-C5, SO-C6, SO-E4, SO-E5 from ADMATECH, and SE-8, SE-15, SE-30, SE-40, SE-15K, SE-30K, SE-40C, UF-305, UF-310, UF-320, UF-345, UF-725 from TOKUYAMA.

Micro spherical silica fillers can be classified into surface-treated spherical silica fillers and surface-untreated spherical silica fillers using a silane coupling agent. The two can also be used in a mixture, but the present invention uses surface-untreated spherical silica fillers.

The average particle size of the micro spherical silica filler particles may be, but is not limited to, 1 to 30 um. Preferably, it is 2 to 10 um, and the maximum particle size should not exceed 30 um.

The specific surface area of the micro spherical silica filler is preferably 1 to 5 m ² /g, and more preferably 1 to 2 m ² /g.

5. Nano spherical silica filler

Nano spherical silica fillers are commercially available from companies such as DENKA's UFP-30M, SFP-20M, SFP-30M, SFP-130MC, and ADMATECH's SO-C1, SO-E1, SO-C2, SO-E2.

The average particle size of the nano spherical silica filler particles may be, but is not limited to, 100 (0.1 um) to 900 nm (0.9 um). Preferably, it is 400 nm (0.4 um) to 600 nm (0.6 um), and the maximum particle size should not exceed 900 nm (0.9 um).

The specific surface area of the nano spherical silica filler is preferably 5 to 30 m ² /g, and more preferably 5 to 15 m ² /g.

The content of the nano spherical silica filler is preferably 12 to 36 wt%, more preferably 18 to 24 wt%. Here, the content is based on the total weight of the adhesive composition (100 wt%). If the content of the nano spherical silica filler is less than 12 wt%, thixotropy may be insufficient, and if it exceeds 36 wt%, viscosity may increase, deteriorating workability and injectability.

6. Stabilizer

A stabilizer is a substance that can improve storage stability at room temperature (25℃). Barbituric acid, boric acid ester compound, aluminum chelate, etc. can be used, and at least one or a mixture of two can be used to improve storage stability at room temperature (25℃).

7. Wetting Dispersant

A wetting and dispersing agent is an additive that can improve the wettability of a solid, prevent the agglomeration of inorganic filler particles, and improve dispersion efficiency.

Commercially available ones include BYK's DISPERBYK-111, BYK-2152, BYK-9077, BYK-9076, DISPERBYK-102, DISPERBYK-103, DISPERBYK-107, DISPERBYK-108, DISPERBYK-109, DISPERBYK-110, DISPERBYK-170, DISPERBYK-171, DISPERBYK-2150, DISPERBYK-2155, DISPERBYK-2164, and DISPERBYK-2200.

Wetting and dispersing agents are classified by amine value, acid value, and non-volatile matter %, and a high wetting and dispersing agent with a non-volatile matter content of 99% or higher is more preferable.

8. Silane coupling agent

Silane coupling agents function as mediators connecting organic and inorganic materials, and are additives that can improve the dispersion efficiency of inorganic fillers and the mechanical strength and adhesiveness of composite materials.

Commercially available ones include KBM-1003, KBE-1003, KBM-303, KBM-402, KBM-403, KBE-402, KEB-403, KBM-5103, KBM-602, KBM-603, KBM-903, KBE-903, KBE-913P, KBM-573, and KBM-575 from Shin-Etsu.

Silane coupling agents can be used with vinyl, epoxy, amino, acryloxy, etc., and at least one or a mixture of two can be used. However, in the present invention, an epoxy silane coupling agent is used.

9. Parcel delivery

The antifoaming agent has the function of preventing the generation of bubbles and foam in advance, and when various substances are mixed and the viscosity is high, it can prevent and resolve the phenomenon of poor coating quality in advance where bubbles do not disappear before the coating dries and remain on the surface of the coating.

Commercially available brands include BYK's BYK-085, BYK-1790, BYK-1791, BYK-1794, BYK-054, BYK-055, BYK-057, BYK-A535, BYK-A501, BYK-A560, BYK-015, BYK-017, BYK-022, and BYK-037.

The foaming agent can be either silicone-based or non-silicon-based, and at least one or a mixture of two types can be used. However, the present invention uses silicone-based foaming agent.

10. Thermoplastic resin for modification

The thermoplastic resin for modification is core shell rubber (CSR), and the core is formed of one or more types of polybutadiene (PBD), acrylic ester, and styrene butadiene rubber.

The shell may be composed of a copolymer of one or more of styrene, acrylic ester, and methyl methacrylate.

Preferably, considering the high bonding strength with epoxy resin, MBS (MethyMethacrylate-Butadiene-Styrene Rubber) is used, which consists of a styrene butadiene rubber core and a methylmethacrylate copolymer as a shell.

Commercially available brands include KANEKA's MX-125, MX-150, MX-153, MX-154, MX-156, MX-257, MX-960, MX-135, MX-136, MX-267, MX-965, MX-217, and MX-553.

In addition, the content of core shell rubber (CSR) as a thermoplastic resin for modification is preferably 5 to 15 wt% based on the weight of the resin composition (100 wt%), and 5 to 10 wt% is more preferable. If the content of core shell rubber (CSR) as a thermoplastic resin is less than 5 wt%, the effect of alleviating the brittle nature and fracture toughness caused by the high filling of the filler is insufficient, making it difficult to prevent cracking of the adhesive composition itself. In addition, if it exceeds 15 wt%, the content of the curable component in the resin composition decreases, so that the interfacial adhesive strength of the adhesive composition itself becomes insufficient after curing, causing delamination between the semiconductor element and the adhesive composition even under a slight impact.

The following two types of thermoplastic resins were used for modification in the comparative examples below.

One thermoplastic resin for modification is an epoxy resin modified with acrylonitrile-nitrile butadiene rubber (NBR). The epoxy equivalent weight is preferably 250 to 450 g/eq. Commercially available ones include EPR-4030, EPR-2000, EPR-21, EPR-1309 from ADEKA, and B6120, B6150, B6240, B6850, B3280, B7150 from SEETEC.

Another thermoplastic resin for modification is carboxyl terminated butadiene acrylonitrile (CTBN), preferably with an acrylonitrile content of 0 to 30%, and commercially available products include CVC's HYPRO 2000X162, HYPRO 1300X31, HYPRO 1300X8, HYPRO 1300X13, HYPRO 1300X13F, HYPRO 1300X9, and HYPRO 1300X18.

The present invention will be further concretized by the following examples. The following examples are merely specific examples of the present invention and are not intended to limit or restrict the protection scope of the present invention.

Examples 1-10

The present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Preparation of underfill adhesive composition

[Composition]

(A) 1st Epoxy Resin: Kukdo Chemical [KDS-8170]

Bisphenol F type epoxy, epoxy equivalent 155~160g/eq, bifunctional

(B) Second Epoxy Resin: Shina Manufacturing [TRD-130]

Resorcinol type epoxy, epoxy equivalent 120~140g/eq, bifunctional

(C) Latent hardener: Fuji Manufacturing [FXR-1121]

Cycloaliphatic polyamine curing agent, average particle size 4um

(D) Micro spherical silica: Denka [FB-7SDC]

Spherical silicon dioxide filler, specific surface area: 1.8 m ² /g, average particle size (d50): 5.4 um

(E) Nano Spherical Silica: Denka [SFP-30M]

Nano spherical silicon dioxide filler, specific surface area: 6.2 m ² /g, average particle size (d ₅₀ ): 600 nm (0.6 um)

(F) Stabilizer: Sigma-Aldrich [barbituric acid], molecular weight 128.1

(G) Wetting and dispersing agent: manufactured by BYK [BYK-2152]

Polyacrylic solid content (Non-Volatile Matter) %: 99% or more,

Amine Value mgKOH/g : 0g

Amine Value mgKOH/g : 0g

(H) Silane coupling agent: Shin-Etsu [KBM-403]

3-Glycidoxypropyltrimethoxysilane (epoxysilane)

(I) Dispersant: BYK [BYK-085]

Polymethylalkylsiloxane (silicon) antifoaming agent solid content (Non-Volatile

Matter)% : 98% or more

(J) Thermoplastic resin for modification: Kaneka [MX-267]

Core Shell Rubber (CSR),

Core: Styrene Butadiene Rubber,

Shell: Methyl methacrylate, also known as MBS (Methy

Methacrylate-Butadiene-Styrene Rubber)

[Manufacturing method]

In a 1,000 g container equipped with a disperser and a thermometer, (A) a first epoxy resin, (B) a second epoxy resin, (F) a stabilizer, (G) a wetting and dispersing agent, (H) a silane coupling agent, (I) an antifoaming agent, and (J) a thermoplastic resin for modification were placed, and the mixture was dispersed at room temperature for 30 minutes at 1,000 to 2,000 RPM. After that, (D) a micro-spherical silica filler and (E) a nano-spherical silica filler were added, and the mixture was further dispersed at 500 to 1,000 RPM for 1 hour. At this time, the temperature was controlled using cooling water so that the temperature of the composition did not rise above 35°C, and finally, (C) a latent curing agent was added, and the mixture was further dispersed for 20 minutes, to prepare a resin composition.

Comparative examples 1-10

[Composition]

The composition is the same as the above example, but the thermoplastic resin for modification (J) was replaced with the following resin.

(K) Thermoplastic resin for modification: Adeka [EPR-4030]

Acrylonitrile-Nitrile Butadiene Rubber

ber(NBR)) modified epoxy resin, epoxy equivalent 365g/eq

(L) Thermoplastic resin for modification: CVC Manufacturing [HYPRO 1300X13]

Carboxyl terminated butadiene acrylonitrile

acrylonitrile(CTBN)), acrylonitrile(Acrylonitrile)%: 26%

[Manufacturing method]

Same as the example, but the thermoplastic resin for modification (J) was replaced with the resin (K) and (L).

[Chemical formula of the composition]

(A)

(B)

(C)

(F)

(H)

(K)

(L)

Raw material name Example 1 Example 2 Example 3 Example 4 Example 5 (A) Component Epoxy resin (weight%) KDS-8170 17 17 17 17 17 (B) Component Epoxy resin (weight%) TRD-130 13 13 13 13 13 (C)Potential curing agent (weight%) FXR-1121 7 7 7 7 7 (D) Micro spherical silica (weight%) FB-7SDC 48 42 36 30 24 (E) Nano spherical silica (weight%) SFP-30M 12 18 24 30 36 (F) Ingredient stabilizer (weight%) barbituric acid 0.2 0.2 0.2 0.2 0.2 (G) Wetting and dispersing agent (weight%) BYK-2152 1.9 1.9 1.9 1.9 1.9 (H) Component Silane coupling agent (weight%) KBM-403 0.5 0.5 0.5 0.5 0.5 (I) Ingredient defoaming agent (weight%) BYK-085 0.4 0.4 0.4 0.4 0.4

Raw material name Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 (A) Component Epoxy resin (weight%) KDS-8170 17 17 17 17 37 (B) Component Epoxy resin (weight%) TRD-130 13 13 13 13 33 (C)Potential curing agent (weight%) FXR-1121 7 7 7 7 27 (D) Micro spherical silica (weight%) FB-7SDC 60 - 18 12 - (E) Nano spherical silica (weight%) SFP-30M - 60 42 48 - (F) Ingredient stabilizer (weight%) barbituric acid 0.2 0.2 0.2 0.2 0.2 (G) Wetting and dispersing agent (weight%) BYK-2152 1.9 1.9 1.9 1.9 1.9 (H) Component Silane coupling agent (weight%) KBM-403 0.5 0.5 0.5 0.5 0.5 (I) Ingredient defoaming agent (weight%) BYK-085 0.4 0.4 0.4 0.4 0.4

Raw material name Example 6 Example 7 Example 8 Example 9 Example 10 (A) Component Epoxy resin (weight%) KDS-8170 17 17 17 17 17 (B) Component Epoxy resin (weight%) TRD-130 11.5 10 8.5 11.8 7 (C)Potential curing agent (weight%) FXR-1121 7 7 7 7 7 (D) Micro spherical silica (weight%) FB-7SDC 30 30 30 30 30 (E) Nano spherical silica (weight%) SFP-30M 26.5 26 24.5 19.2 21 (F) Ingredient stabilizer (weight%) barbituric acid 0.2 0.2 0.2 0.2 0.2 (G) Wetting and dispersing agent (weight%) BYK-2152 1.9 1.9 1.9 1.9 1.9 (H) Component Silane coupling agent (weight%) KBM-403 0.5 0.5 0.5 0.5 0.5 (I) Ingredient defoaming agent (weight%) BYK-085 0.4 0.4 0.4 0.4 0.4 (J) Thermoplastic resin for component modification MX-267 5 7 10 12 15 (K) Thermoplastic resin for component modification EPR-4030 - - - - - (L) Thermoplastic resin for component modification HYPRO 1300X13 - - - - -

Raw material name Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 (A) Component Epoxy resin (weight%) KDS-8170 17 17 17 17 37 (B) Component Epoxy resin (weight%) TRD-130 11.5 10 8.5 11.8 28 (C)Potential curing agent (weight%) FXR-1121 7 7 7 7 27 (D) Micro spherical silica (weight%) FB-7SDC 30 30 30 30 - (E) Nano spherical silica (weight%) SFP-30M 26.5 26 24.5 19.2 - (F) Ingredient stabilizer (weight%) barbituric acid 0.2 0.2 0.2 0.2 0.2 (G) Wetting and dispersing agent (weight%) BYK-2152 1.9 1.9 1.9 1.9 1.9 (H) Component Silane coupling agent (weight%) KBM-403 0.5 0.5 0.5 0.5 0.5 (I) Ingredient defoaming agent (weight%) BYK-085 0.4 0.4 0.4 0.4 0.4 (J) Thermoplastic resin for component modification MX-267 - - - - - (K) Thermoplastic resin for component modification EPR-4030 5 7 - - 2.5 (L) Thermoplastic resin for component modification HYPRO 1300X13 - - 10 12 2.5

[Physical property evaluation]

1. Glass Transition and CTE (Coefficient of Thermal Expansion) measurement

The measurement sample was prepared by filling a resin composition into a circular Teflon jig measuring 6 mm in width and 20 mm in height and curing it in an oven at 100°C for 1 hour to obtain a test piece.

The obtained test specimens were cut into sizes of approximately 2 to 5 mm in height and heated at a rate of 10°C per minute using TA's Q400 equipment, running two cycles up to 200°C, and the CTE (Coefficient of Thermal Expansion) value was expressed based on the glass transition point.

Glass transition refers to the period in which a sample changes from a hard state like glass to a soft state like rubber.

CTE (Coefficient of Thermal Expansion) is a value that indicates the extent to which the initial sample length, converted to 1m, increases or decreases when the temperature rises by 1℃. A large value means a large amount of expansion, and a small value means a small amount of expansion.

CTE (Coefficient of Thermal Expansion) is expressed as CTE1 and CTE2, and the temperature (℃) range lower than the glass transition temperature (℃) is expressed as CTE1, and the temperature (℃) range higher than the glass transition temperature (℃) is expressed as CTE2.

2. Injectability measurement

The injection molding machine is made of two slide glasses, one on the top and one on the bottom, and a space measuring 6 cm in length, 1 cm in width, and 50 um in thickness is secured in the center of the slide glass. After discharging approximately 0.2 g of the resin composition, the time required for the resin composition to be filled to 1 cm (10 mm) is checked, and the temperature is expressed as a value at room temperature (25°C) and 50°C.

3. Measurement of viscosity and thixotropic values

Viscosity was measured using Brookfield's Viscometer HBDV-Ⅱ at 25℃, and a shear rate of 5 RPM was applied.

The thixotropic value was obtained by dividing it by the viscosity value that is 10 times different from 0.5 RPM/5 RPM. Viscosity refers to the resistance of a fluid (shear stress and tensile stress due to friction) when its shape changes.

4. Measurement of thermal shock test (Temperature Cycle Test)

The thermal shock test method was conducted under the JESD22-A104 G (-40℃ to 125℃) test conditions, and after evaluation, C-SAM was used to confirm whether peeling occurred.

Thermal shock testing is a method for evaluating the resistance of components to sudden temperature changes. It is a rapid temperature change evaluation process in which the adhesive composition is repeatedly exposed to extremely low or high temperatures for a specific number of times starting at room temperature after curing.

5. Adhesion Test

The adhesion test was measured using a Condor Sigma device from XYZTEC, and a curing test piece was obtained by placing a 0.8 cm square material on a FR4 PCB. The actual bond line thickness of the adhesive composition for the 0.8 cm square material was 0.4 mm.

Adhesion refers to the bonding strength of the interface between an adhesive and an adherend, and can generally be said to be the force that sticks two objects together. The unit of adhesive strength is the force per length, expressed as kgf/cm.

Example 1 2 3 4 5 Glass Transition℃ 118℃ Coefficient of Thermal Expansion (CTE)
CTE1 / CTE2 (ppm/℃) 35.5 / 88.7 32.3 / 82.5 31.8 / 79.7 31.4 / 81.4 31.5 / 81.5 Injectable
25℃ / 50℃ 3 minutes 30 seconds / 1 minute 31 seconds 2 minutes 43 seconds / 1 minute 10 seconds 2 minutes 30 seconds / 58 seconds 2 minutes 57 seconds / 1 minute 21 seconds 3 minutes 20 seconds / 1 minute 28 seconds Viscosity (Cps) 29,400 21.700 20.700 26.900 28.300 Chic value 1.04 0.95 0.90 0.85 0.80 Thermal shock test
(Number of peelings / Number of samples) 15 / 30 Adhesion test (kgf/cm²) 20 kgf/cm²

Comparative example 1 2 3 4 5 Glass Transition℃ 118℃ Coefficient of Thermal Expansion (CTE)
CTE1 / CTE2 (ppm/℃) 39.2 / 91.5 37.8 / 89.5 34.1 / 86.2 35.3 / 88.5 95.4 / 231.4 Injectable
25℃ / 50℃ 15 minutes / 3 minutes 54 seconds 4 minutes 30 seconds / 2 minutes 15 seconds 3 minutes 40 seconds / 1 minute 40 seconds 3 minutes 58 seconds / 1 minute 57 seconds 58 seconds / 15 seconds Viscosity (Cps) 78,500 50.100 36.900 41.200 4.200 Chic value 1.11 0.60 0.79 0.70 1.02 Thermal shock test
(Number of peelings / Number of samples) 15 / 30 30 / 30 Adhesion test (kgf/cm²) 20 kgf/cm² 28 kgf/cm²

Example 6 7 8 9 10 Glass Transition℃ 116℃ 112℃ 102℃ 118℃ 91℃ Coefficient of Thermal Expansion (CTE)
CTE1 / CTE2 (ppm/℃) 32.4 / 90.7 30.2 / 77.3 31.5 / 73.4 30.1 / 76.5 31.5 / 74.8 Injectable
25℃ / 50℃ 2 minutes 41 seconds / 1 minute 11 seconds 2 minutes 45 seconds / 1 minute 14 seconds 2 minutes 46 seconds / 1 minute 14 seconds 2 minutes 42 seconds / 1 minute 10 seconds 2 minutes 58 seconds / 1 minute 20 seconds Viscosity (Cps) 21,600 22.900 24.500 21.200 26.800 Chic value 0.9 0.90 0.90 0.90 0.90 Thermal shock test
(Number of peelings / Number of samples) 0 / 30 0 / 30 0 / 30 6 / 30 0 / 30 Adhesion test (kgf/cm²) 22 kgf/cm² 25 kgf/cm² 24 kgf/cm² 22 kgf/cm² 10 kgf/cm²

Comparative example 6 7 8 9 10 Glass Transition℃ 100℃ 89℃ 95℃ 72℃ 113℃ Coefficient of Thermal Expansion (CTE)
CTE1 / CTE2 (ppm/℃) 30.3 / 77.7 31.2 / 73.5 30.2 / 76.3 31.5 / 74.1 90.1 / 197.3 Injectable
25℃ / 50℃ 7 minutes 52 seconds / 3 minutes 33 seconds 9 minutes 30 seconds / 4 minutes 10 seconds 8 minutes 20 seconds / 4 minutes 2 seconds 10 minutes 45 seconds / 4 minutes 50 seconds 59 seconds / 18 seconds Viscosity (Cps) 23.800 25.500 24.600 27.600 5.100 Chic value 0.90 0.90 0.90 0.90 1.01 Thermal shock test
(Number of peelings / Number of samples) 9 / 30 0 / 30 6 / 30 30 / 30 9 / 30 Adhesion test (kgf/cm²) 21 kgf/cm² 21 kgf/cm² 10 kgf/cm² 6 kgf/cm² 26 kgf/cm²

According to Tables 1 and 2, Tables 5 and 6, when micro-spherical silica and nano-spherical silica fillers were used within the content ranges of Examples 1 to 5, the injectability was improved, and a slight decrease in the CTE (Coefficient of Thermal Expansion) value and a large difference in the viscosity and thixotropic value were observed.

In addition, according to Tables 3 and 4, Tables 7 and 8, when the thermoplastic core shell rubber (CSR: Core Shell Rubber) resin for modification of Examples 6 to 10 was used, it was confirmed that sample peeling was prevented after the thermal shock test (Temperature Cycle Test), the change in glass transition was minimized, and the injectability was maintained.

Comparative Examples 6 to 10 showed significant differences in glass transition and injectability compared to other types of modified thermoplastic resins such as acrylonitrile-nitadiene butadiene rubber (NBR) and carboxyl terminated butadieneacrylonitrile (CTBN) resins.

Examples 1 to 5 contained 12 to 36 wt% of the nano-spherical silica filler based on the total weight (100%) of the adhesive composition, and had the effect of lowering the viscosity and thixotropic value. Due to the change in lowering the viscosity and thixotropic value, the injectability was improved, and it was confirmed that the CTE1 and CTE2 values were slightly reduced. A lower CTE (Coefficient of Thermal Expansion) value may mean that shrinkage and expansion of the adhesive composition were reduced. In addition, it was confirmed that 50% of the sample peeling occurred compared to Comparative Example 5 that did not include (D) and (E) fillers after the thermal shock test (Temperature Cycle Test). This may mean that the adhesive reliability was improved due to the reduction in mechanical and thermal stress between the substrate and the chip by lowering the CTE (Coefficient of Thermal Expansion) by increasing the filling ratio of the filler.

Examples 6 to 10 contained 5 to 15 wt% of thermoplastic core shell rubber (CSR) resin for modification based on the weight of the resin composition (100 wt%), and the change in glass transition was minimized and there was no change in injectability. In addition, it was possible to prevent sample peeling after a thermal shock test (Temperature Cycle Test). This may mean that the stress and brittle nature of the adhesive composition itself were alleviated, thereby increasing the fracture toughness.

Comparative Example 1 is a resin composition using only micro spherical silica filler, and compared to Examples 1 to 5, the viscosity and thixotropic value were high, resulting in poor injectability. In addition, the CTE value was slightly higher than that of Examples 1 to 5, which may mean that the expansion of the resin composition was slightly higher than that of Examples 1 to 5.

Comparative Examples 2 to 4 used nano-spherical silica fillers, but it can be confirmed that the viscosity increases beyond the desired weight (12 to 36 wt%). In addition, it can be confirmed that the thixotropic value decreases, but Comparative Examples 2 to 4, which have a low thixotropic value but a high viscosity compared to Examples 1 to 5, did not have good injectability.

Comparative Example 5 is a resin composition that does not contain micro spherical silica or nano spherical silica fillers. It can be confirmed that the injection property is good unlike Examples 1 to 5 and Comparative Examples 1 to 4 due to low viscosity. However, it can be confirmed that the CTE (Coefficient of Thermal Expansion) value is more than twice as high compared to Examples 1 to 5 and Comparative Examples 1 to 4. This means that the expansion of the resin composition of Comparative Example 5 is not more than twice as good as that of Examples 1 to 5 and Comparative Examples 1 to 4. In addition, it was confirmed that 100% of the sample peeled off after the thermal shock test (Temperature Cycle Test). The CTE (Coefficient of Thermal Expansion) is more than twice as high compared to Examples 1 to 5 and Comparative Examples 1 to 4. This may mean that the shrinkage and expansion values are high, and the mechanical and thermal stresses between the substrate and the chip are increased, which may result in lowered bond reliability.

Comparative Examples 6 and 7 contained 5 to 10 wt% of acrylonitrile-nitadiene rubber (NBR) modified epoxy resin for modification based on the weight of the resin composition (100 wt%), and a large wt% was used compared to the core shell rubber (CSR: Core Shell Rubber) resin so that the stress and brittle properties of the adhesive composition itself were alleviated and the fracture toughness was effective, but the injectability was poor. In addition, it was confirmed that the change in the glass transition was greatly reduced.

Comparative Examples 8 and 9 contained 10 to 12 wt% of the carboxyl terminated butadieneacrylonitrile (CTBN) resin content for modification based on the weight of the resin composition (100 wt%). After a temperature cycle test, 20% of the sample was peeled off in Comparative Example 8 (10 wt%), and 100% of the sample was peeled off in Comparative Example 9 (12 wt%). The injection property was poor due to the same phenomenon as the acrylonitrile-nitadiene rubber (NBR) modified epoxy resin. In the case of carboxyl terminated butadieneacrylonitrile (CTBN) resin, the content of the curable component in the resin composition was drastically reduced, resulting in poor interfacial adhesion of the adhesive composition itself after curing. This may mean that due to insufficient adhesive strength, severe delamination occurs between the semiconductor element and the adhesive composition even under slight thermal shock.

Comparative Example 10 contained 2.5 wt% of acrylonitrile-nitadiene rubber (NBR) modified epoxy resin and carboxyl terminated butadieneacrylonitrile (CTBN) resin as the thermoplastic resin for modification, and it was confirmed that 30% of the sample peeled off after the thermal shock test (Temperature Cycle Test). By using core shell rubber (CSR) resin, the stress and brittle properties of the adhesive composition itself were alleviated, and the fracture toughness was alleviated. However, since no filler was used, the CTE (Coefficient of Thermal Expansion) value increased, which increased the shrinkage and expansion values, and the mechanical and thermal stress between the substrate and the chip increased, which lowered the reliability of the adhesion between the substrate and the chip, which may mean that the sample peeled off after the thermal shock test (Temperature Cycle Test).

Since the micro-spherical silica filler is amorphous, it has low thermal expansion and thermal conductivity. The thermal expansion coefficient of the amorphous silica filler is approximately 0.5 ppm/K, and the thermal conductivity is 1.4 W/mK. In addition, if the shape of the micro-spherical silica filler particles is square, the fluidity, dispersibility, and filling properties deteriorate, and the wear of the manufacturing device may also progress rapidly. For these reasons, it is advantageous to use a spherical silica filler. However, even the micro-spherical silica filler has a problem in that if the filling rate is excessively high, the viscosity increases, which reduces workability and injectability (fluidity). It is presumed that a suitable method for solving the problem of increased viscosity is to fill the spaces between the micro-unit spherical silica filler particles with nano-unit spherical silica filler, which can solve the problem of increased viscosity and lower the expansion rate while also reducing the CTE (Coefficient of Thermal Expansion) value by high-filling the filler content.

In addition, as the filling ratio of the filler increases, the brittle property of the adhesive composition itself increases, and as the brittle property increases, the fracture toughness decreases. In addition, although the thermal stress is alleviated as the filling ratio of the filler increases, the stress of the adhesive composition itself is not alleviated. In order to alleviate the brittle property of the adhesive composition itself to increase the fracture toughness and alleviate the stress of the adhesive itself, a thermoplastic resin for modification must be used.

Representative types of thermoplastic resins for modification include core shell rubber (CSR), carboxyl terminated butadieneacrylonitrile (CTBN), and acrylonitrile-nitadiene butadiene rubber (NBR), but it is presumed that the resin is a composite resin that has a core shell rubber (CSR) resin that has been spheroidized in nm units. In the case of underfill, flowability and glass transition are very important factors. In the case of core shell rubber (CSR) resin, it is a resin that can supplement adhesives with a small usage amount as a resin that has been spheroidized in nm units, and it is presumed to be a resin that has very advantageous flowability and can be used while maintaining the glass transition as much as possible.

The present invention described above is not limited to the above-described embodiments and the attached drawings, and it will be apparent to a person skilled in the art to which the present invention pertains that various substitutions, modifications, and changes are possible within a scope that does not depart from the technical spirit of the present invention.

Claims (11)

A first epoxy resin composition comprising: 13 to 21 wt% of a first epoxy resin; 5 to 15 wt% of a second epoxy resin; 2 to 10 wt% of a latent hardener; 24 to 48 wt% of a micro-spherical silica filler; 12 to 36 wt% of a nano-spherical silica filler; 0.05 to 0.5 wt% of a stabilizer; 0.5 to 5.0 wt% of a wetting and dispersing agent; 0.1 to 1.0 wt% of a silane coupling agent; and 0.1 to 1.0 wt% of a defoaming agent.
An underfill adhesive composition, wherein the second epoxy resin has an epoxy equivalent of 120 to 140 g/eq, a viscosity of 300 to 1,000 cps, and is a bifunctional resorcinol diglycidyl ether.
In the first paragraph,
In addition to the above underfill adhesive composition,
An underfill adhesive composition further comprising 5 to 15 wt% of a thermoplastic resin for modification.
In the first paragraph,
An underfill adhesive composition, wherein the first epoxy resin has an epoxy equivalent of 155 to 160 g/eq, a viscosity of 1,000 to 2,000 cps, and is a bifunctional bisphenol F type.
delete In the first paragraph,
An underfill adhesive composition characterized in that the latent curing agent is a solid at 20 to 25°C and is a modified aliphatic polyamine.
In the first paragraph,
An underfill adhesive composition, characterized in that the above micro spherical silica filler has a particle diameter of 1 to 30 um and a specific surface area of 1.0 to 5.0 m ² /g.
In the first paragraph,
An underfill adhesive composition, wherein the above nano spherical silica filler has a particle diameter of 100 to 900 nm and a specific surface area of 5 to 30 m ² /g.
In the first paragraph,
An underfill adhesive composition, characterized in that the stabilizer is at least one of barybutic acid, a boric acid ester compound, aluminum, and a chelate.
In the first paragraph,
An underfill adhesive composition, characterized in that the above wetting and dispersing agent has a solid content (NON-VOLATILE MATTER) of 99% or more.
In the first paragraph,
An underfill adhesive composition characterized in that the above silane coupling agent is a mixture of at least one of a vinyl group, an epoxy group, an amino group, and an acryloxy group.
In the second paragraph,
An underfill adhesive composition characterized in that the thermoplastic resin for modification is a core shell rubber (CSR) having a viscosity of 5,000 to 8,000 cps and a particle size of 50 to 150 nm.