Chemical shrinkage and diffusion-controlled reaction of an epoxy molding compound

Tai, H.; Chou, Hui-Lung

doi:10.1016/s0014-3057(99)00278-5

Cited by 32 publications

(18 citation statements)

References 22 publications

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“…At the beginning of the reaction process, the diffusion effects can be neglected, whereas in the vicinity of vitrification, the overall rate of reaction depends also on diffusion phenomena. Because the shift from a chemically to a diffusion-controlled reaction regime is progressive and does not occur exactly at a given time, an overall reaction rate constant K total has been proposed by Rabinowitch, 3,4,28 such as…”

Section: Curing Kinetics Modelingmentioning

confidence: 99%

“…They are known to provide great chemical and solvent resistances, mechanical responses ranging from great flexibility to high strength and hardness, good thermal and dimensional stabilities, and a high adhesive strength to most substrates, as well as very good electrical insulation properties. [1][2][3] However, the final performance of such materials is strongly dependent on the processing conditions applied. To fully appreciate the conversion of an epoxy system into a finished part, a full understanding of the curing process is required to determine the optimal curing conditions and thus reach the ultimate properties of the material.…”

Section: Introductionmentioning

confidence: 99%

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TTT‐cure diagram of an anhydride‐cured epoxy system including gelation, vitrification, curing kinetics model, and monitoring of the glass transition temperature

Teil

Page

Michaud

et al. 2004

J of Applied Polymer Sci

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ABSTRACT:The curing reaction of an epoxy resin [diglycidyl ether of bisphenol A (DGEBA)] combined with a methyl-hexahydrophtalic anhydride (MHHPA) hardener and a benzyldimethylamine (BDMA) accelerator was studied over a temperature range of 60 -140°C to build its isothermal time-temperature-transformation (TTT)-cure diagram. This includes gelation and vitrification measurements using rheological measurement techniques, monitoring of the glass transition temperature and the reaction kinetics by differential scanning calorimetry, and determination of the following critical glass transition temperatures: T g0 , Gel T g , and T gϱ . A new curing kinetics model, based on the Sesták-Berggren model, was developed including both chemicaland diffusion-controlled stages of reaction. Then, the TTTcure diagram was built by numerical integration of the kinetics model, and good agreement was obtained by comparison with experimental data. Additionally, for the first time, this model takes into account the incomplete cure, which occurs when the thermosetting system is cured below its ultimate glass transition temperature, leading to a more realistic description of the cure evolution after vitrification.

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Section: Curing Kinetics Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

TTT‐cure diagram of an anhydride‐cured epoxy system including gelation, vitrification, curing kinetics model, and monitoring of the glass transition temperature

Teil

Page

Michaud

et al. 2004

J of Applied Polymer Sci

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“…However, in the samples, initial deformation at room temperature may exist because of the cure shrinkage of molding compound after PMC process. During the PMC process, due to the polymerization of epoxy and fillers, the formation of highly cross-linked polymers results in a significant decrease in the specific volume [14]. However, the deformation caused by the cure shrinkage was not considered in this paper.…”

Section: Out-of-plane Deformationmentioning

confidence: 99%

Optimal Material Properties of Molding Compounds for MEMS Package

Kim

Lee

Zhang

et al. 2014

IEEE Trans. Compon., Packag. Manufact. Technol.

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In this paper, an optimization study of molding compounds for a microelectromechanical systems (MEMS) sensor package has been performed. A comprehensive finite element analysis model was established for the MEMS sensor package to assess the stresses and deformations when the package was subjected to temperature loading. A series of stress relaxation tests were performed to characterize the viscoelastic material properties of a molding compound over temperature with dynamic mechanical analysis. A master curve for the molding compound was constructed by a proper shift function and the Prony pairs were obtained by curve fitting to be implemented in the simulation. To validate the simulation result, the thermal behavior of the MEMS package was measured. The digital image correlation technique was employed to observe the real-time deformation of the package exposed to temperature loading. The out-of-plane deformation of the package was compared with the simulation result. With the validated simulation model, the optimization study was conducted. By the process simulation, it has been shown that most of the thermal stress on the MEMS sensor chip was generated during the cooling process. Thus, a detailed cooling profile was developed by the transient heat analysis and applied to the parametric study. The modulus, coefficient of thermal expansion (CTE), and glass transition temperature (T g ) of molding compound were investigated. The result shows that a low modulus, low CTE, and low T g molding compound can minimize the thermal stress on MEMS sensor die.

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“…In a more recent publication, Hong et al 11 investigated the effect of mold curing shrinkage dependent on molding pressure, temperature, and degree of cure, showing that by considering only the thermal shrinkage the amount of warpage in a package is underestimated. Further investigation by developing a cure-dependent stress-strain relationship for warpage studies in IC packaging was carried out by Hong et al 12 The cure reaction kinetics and chemical shrinkage of a filled-epoxy molding compound were studied by Tai et al, 13 who characterized the curing reaction of the mold as reacting first autocatalytically then switching to a diffusion-controlled reaction. They also stated an even higher contribution of the chemical reaction shrinkage than thermal contraction for the overall volume contraction on cooling after the molding process.…”

Section: Introductionmentioning

confidence: 99%

Impact of Reaction Shrinkage on Stress in Semiconductor Packages

Mengel

Mahler

2009

Journal of Elec Materi

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The reliability of a semiconductor package is strongly influenced by the adhesion and temperature behavior of the package encapsulant. This study considers the effect of mold shrinkage during the encapsulation molding process. Four commercially available molds were investigated using warpage and thermomechanical analysis. It could be demonstrated that, for all four types, when molded on a silicon substrate, the temperature at which no stress occurred was in a range of 28-60°C above the molding temperature. This is caused by the shrinkage due to a crosslinking reaction of the mold polymer during the molding process. For a more precise understanding and simulation of the stress behavior inside a molded package, the effect of reaction shrinkage has to be considered.

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Chemical shrinkage and diffusion-controlled reaction of an epoxy molding compound

Cited by 32 publications

References 22 publications

TTT‐cure diagram of an anhydride‐cured epoxy system including gelation, vitrification, curing kinetics model, and monitoring of the glass transition temperature

TTT‐cure diagram of an anhydride‐cured epoxy system including gelation, vitrification, curing kinetics model, and monitoring of the glass transition temperature

Optimal Material Properties of Molding Compounds for MEMS Package

Impact of Reaction Shrinkage on Stress in Semiconductor Packages

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