Monitoring of properties of epoxy molding compounds used in electronics for protection and hermetic sealing of microcircuits

Kokatev, A N; Iakovleva, N M; Stepanova, K. V.; Ershova, N. Yu.; Belov, K V

doi:10.1088/1757-899x/665/1/012006

Cited by 5 publications

(4 citation statements)

References 4 publications

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“…Whereas the inorganic fillers controlling the mechanical properties of the EMC ( e.g., the Young’s modulus and linear expansion coefficient) 23 account for 70–90 wt % of the EMC, 24 the resin, which causes the adhesion between the EMC and the semiconductor chip or lead frame, represents ∼14 wt % of the EMC. Because this study focuses on the adhesion interface between the epoxy resin component and the surface of the lead frame, fillers that do not contribute directly to adhesion were excluded from the modeling.…”

Section: Methodsmentioning

confidence: 99%

Elucidation of Adhesive Interaction between the Epoxy Molding Compound and Cu Lead Frames

Tsurumi¹,

Tsuji

Masago

et al. 2021

ACS Omega

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Clarification of adhesive interactions in semiconductor packages can improve reliability of power electronics. In this study, the adhesion interfaces between the epoxy molding compound and Cu-based lead frames were analyzed using the density functional theory. A resin fragment was prepared based on the polymer framework formed in the curing reaction of epoxy cresol novolac (ECN) and phenol novolac (PN), which are typical molding materials. The resin fragment was optimized on the surfaces of Cu and Cu 2 O. We calculated the charge density differences for adhesion structures and discussed the origin of adhesive interactions. The ECN–PN fragment’s adhesion to the Cu surface relied mainly on dispersion forces, whereas in the case of Cu 2 O, the resin bonded chemically to the surface via (1) σ-bonds formed between the ECN–PN’s OH group oxygen and coordinatively unsaturated copper (Cu CUS ) and (2) hydrogen bonds between resin’s OH groups and coordinatively unsaturated oxygen (O CUS ) located close to to Cu CUS , resulting in a stable adhesive structure. The energy required to detach the resin fragment from the optimized structure was determined using the nudged elastic band method in each model of the adhesive interface. Morse potential curve was used to approximate the obtained energy, and the energy differentiation by detachment distance yielded the theoretical adhesive force. The maximum adhesive stress was 1.6 and 2.2 GPa for the Cu and Cu 2 O surfaces, respectively. The extent to which the ECN–PN fragment bonded to the Cu 2 O surface stabilized was 0.5 eV higher than in the case of the Cu surface.

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Section: Methodsmentioning

confidence: 99%

Elucidation of Adhesive Interaction between the Epoxy Molding Compound and Cu Lead Frames

Tsurumi¹,

Tsuji

Masago

et al. 2021

ACS Omega

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“…The results of the computer-vision numerical analysis of the SEM images resulted in a higher CS value for water-stained inks, indicating that the particles were more vertically oriented than those in water-free samples, which corroborated the proposed mechanisms in a quantitative fashion. The proposed concept in this study is extremely simple and does not require any additional cost to the one required for the preparation of the common epoxy–filler composites, which is expected to be extendable for the manufacture of various epoxy-based formulations with fillers other than alumina [ 1 , 2 , 3 , 6 , 7 , 9 , 10 , 31 , 32 , 33 ], and the products will be useful in a variety of applications where 3D printing of epoxy composite materials is necessary.…”

Section: Discussionmentioning

confidence: 99%

“…Epoxy is one of the most widely used thermosetting polymers in a wide variety of applications because of its excellent mechanical strength and thermal and chemical stability [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Recently, several approaches for the direct ink writing (DIW) of epoxy-based materials have been introduced [ 12 , 13 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

Direct-Writable and Thermally One-Step Curable “Water-Stained” Epoxy Composite Inks

et al. 2022

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In this study, a simple method for preparing direct-writable and thermally one-step curable epoxy composite inks was proposed. Specifically, colloidal inks containing a mixture of ordinary epoxy resin and anhydride-type hardener with the suspended alumina microplates, as exemplary fillers, are “stained” with small amounts of water. This increases the elasticity of the ink via the interparticle capillary attraction and promotes curing of the epoxy matrix in low-temperature ranges, causing the three-dimensional (3D) printed ink to avoid structural disruption during one-step thermal curing without the tedious pre-curing step. The proposed mechanisms for the shape retention of thermally cured water-stained inks were discussed with thorough analyses using shear rheometry, DSC, FTIR, and SEM. Results of the computer-vision numerical analysis of the SEM images reveal that the particles in water-stained inks are oriented more in the vertical direction than those in water-free samples, corroborating the proposed mechanisms. The suggested concept is extremely simple and does not require any additional cost to the one required for the preparation of the common epoxy–filler composites, which is thus expected to be well-exploited in various applications where 3D printing of epoxy-based formulations is necessary.

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“…During molding, epoxy resin is liquefied by high temperature and high pressure and forced through a mold chase over the die and leadframe [9]. The epoxy resin has well-balanced physical and chemical properties (high adhesion strength, chemical strength, thermal resistance and moisture resistance, low viscosity and shrinkage ratio), low cost and good aesthetic properties [10]. The cross-link density of molding molecular chains increases as time increases during molding and post-mold curing [11].…”

mentioning

confidence: 99%

Study of the Impact of Curing Condition on Flexural Strength of a Very Thin Semiconductor Package

Talledo¹

2021

JERR

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Thinner semiconductor package is becoming popular especially in consumer electronics applications. As package becomes thinner, it is more vulnerable to package crack when subjected to external load. It is important to ensure that the package is strong enough to resist package cracking. This paper presents the study of package flexural strength under different epoxy mold compound curing condition. A 3-point bend test was done to characterize the breaking strength of the package that was subjected to post-mold curing. It was then compared to the strength of the package not subjected to post-mold curing (PMC). Results of the bend testing showed that the package flexural strength is much lower when the package is not subjected to post-mold curing. This study demonstrates that the measurement of flexural strength can be used to determine if the package has undergone post-mold curing or not. Performing the right post-mold curing of the thin molded package is required to ensure higher flexural strength.

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Monitoring of properties of epoxy molding compounds used in electronics for protection and hermetic sealing of microcircuits

Cited by 5 publications

References 4 publications

Elucidation of Adhesive Interaction between the Epoxy Molding Compound and Cu Lead Frames

Elucidation of Adhesive Interaction between the Epoxy Molding Compound and Cu Lead Frames

Direct-Writable and Thermally One-Step Curable “Water-Stained” Epoxy Composite Inks

Study of the Impact of Curing Condition on Flexural Strength of a Very Thin Semiconductor Package

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