US 12,444,693 B2
Electromagnetic interference shielding device comprising a flame retarding, thermal interface material composite, and method for preparation thereof
Chi Ho Kwok, Hong Kong (HK); Xiaohua Chen, Hong Kong (HK); Wai Chung Li, Hong Kong (HK); and Chenmin Liu, Hong Kong (HK)
Assigned to Nano and Advanced Materials Institute Limited, Hong Kong (HK)
Filed by Nano and Advanced Materials Institute Limited, Hong Kong (HK)
Filed on Nov. 19, 2021, as Appl. No. 17/530,483.
Claims priority of provisional application 63/118,021, filed on Nov. 25, 2020.
Prior Publication US 2022/0165681 A1, May 26, 2022
Int. Cl. H01L 23/552 (2006.01); C01B 32/21 (2017.01); H01F 1/00 (2006.01); H01F 1/34 (2006.01); B82Y 25/00 (2011.01); B82Y 30/00 (2011.01); C01G 49/08 (2006.01)
CPC H01L 23/552 (2013.01) [C01B 32/21 (2017.08); H01F 1/0018 (2013.01); H01F 1/344 (2013.01); B82Y 25/00 (2013.01); B82Y 30/00 (2013.01); C01G 49/08 (2013.01); C01P 2004/20 (2013.01); C01P 2004/64 (2013.01); C01P 2006/40 (2013.01); C01P 2006/42 (2013.01)] 16 Claims
OG exemplary drawing
 
1. An electromagnetic interference (EMI) shielding device comprising a flame retarding, thermal interface material composite with shielding effectiveness of 30-50 dB at a frequency range of 0 to 10 GHz, a through plane thermal conductivity of no less than 30 W/mK and an in-plane thermal conductivity of no less than 10 W/mK, a dielectric withstanding voltage of no less than 1 kV/mm, the composite comprising:
at least a first layer of self-aligned, carbon-based materials formed on at least one dielectric layer having a carbon content of about 85 to 99.9% associated with superparamagnetic particles with magnetic field strength of 60-90 amu/g such that an inclined angle between the carbon-based materials and a horizontal plane of the dielectric layer is adjustable between 90 and 45 degrees in the presence of less than 1 Tesla of magnetic field;
at least a second layer of fillers comprising a blend of dielectric isotropic heat transfer materials with a thermal or UV curable polymer or phase change polymer,
the first layer comprising a plurality of ceramic fillers associated with a polymer to form a polymer matrix,
each of the self-aligned, carbon-based materials having an aspect ratio of 3:1 to 6:1 and an average particle size between 0.1 and 1.0 mm,
the superparamagnetic particles having an average particle size of less than 10 μm, magnetic field strength of about 60 to 90 amu/g and providing the self-aligned driving force, carbon-based materials with an adjustable inclined angle between 90 and 45 degrees about the horizontal plane of the dielectric layer in the presence of less than 1 Tesla of magnetic field, wherein the concentration of the superparamagnetic particles is 2-5 wt. % to the weight of carbon-based materials,
at least 20% of the first layer overlaps and at least 20% of the second layer when the carbon-based materials are self-aligned in the presence of the magnetic field and tilted to an angle from 0 to about 45 degrees against the direction of the magnetic field at the same plane.