Epoxy/BaTiO3 composite films and pastes for high dielectric constant and low-tolerance embedded capacitors fabrication in organic substrates

Epoxy/BaTiO3 composite embedded capacitor films (ECFs) were newly designed for high dielectric constant and low-tolerance (less than 5%) embedded capacitor fabrication for organic substrates. In terms of material formulation, ECFs are composed of a specially formulated epoxy resin and latent curing agent, and in terms ofa coating process, a comma roll coating method is used for uniform film thickness in large area. The dielectric constant of ECF in high frequency range (0.5 3 GHz) is measured using the cavity resonance method. In order to estimate dielectric constant, the reflection coefficient is measured with a network analyzer. The dielectric constant is calculated by observing the frequencies of the resonant cavity modes. Calculated dielectric constants in this frequency range are about 3/4 of the dielectric constants at 1 MHz. This difference is due to the decrease of the dielectric constant of the epoxy matrix. The dielectric relaxation of barium titanate (BaTiO3: BT) powder is not observed within measured frequency. An alternative material for embedded capacitor fabrication is epoxy/BaTiO3 composite embedded capacitor paste (ECP). It uses similar materials formulation like ECF and a screen printing method for film coating. The screen printing method has the advantage of forming a capacitor partially in the desired part. However, the screen printing makes surface irregularities during mask peel-off. Surface flatness is significantly improved by adding some additives and by applying pressure during curing. As a result, a dielectric layer with improved thickness uniformity is successfully demonstrated. Using epoxy/BaTiO3 composite ECP, a dielectric constant of 63 and specific capacitance of 5.1 nF/cm2 were achieved.
Publisher
Institute of Electrical and Electronics Engineers
Issue Date
2005-10
Language
ENG
Keywords

Dielectric constant; embedded capacitor; polymer-ceramic composite; tolerance

Citation

IEEE TRANCSACTIONS ON ELECTRONICS PACKAGING MANUFACTURING v.28 no.1521-334X pp.297 - 303

ISSN
1521-334X
URI
http://hdl.handle.net/10203/1244
Appears in Collection
EE-Journal Papers(저널논문)
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