TY - GEN
T1 - Novel pore-sealing technology in the preparation of low-k underfill materials for RF applications
AU - Hsu, Kuo Yuan
AU - Perng, Leu-Jih
PY - 2008/10/2
Y1 - 2008/10/2
N2 - Underfill materials had been widely employed in the flipchip packaging to fill the gaps of solder bumps connecting IC chip and organic substrate in order to prevent failure of the solder joints. For radio-frequency (RF) device applications, underfill materials should possess low dielectric constant to alleviate power loss at high-frequency, in addition to good thermal and mechanical properties. In this study, a novel approach of incorporating porosity through porous silica filler was attempted to develop low-k underfill materials. An inorganic, sacrificial material, hexamethylcyclotrisiloxane (D3), was used to temporarily seal the interconnected pores in the porous silica at temperature < 95°C by thermal and solvent pretreatment methods, and was later removed thermally at 125-165°C during the crosslinking reaction of underfill materials. For underfill materials with 15% filler content, a 7.8% reduction in dielectric constant has been successfully demonstrated and achieved by pore sealing of porous silica (60% porosity) using solvent pretreatment, while maintaining the mechanical strength of porous silica, 2.6 GPa. Moreover, the adhesion between epoxy and porous silica in the underfull materials was found to critical in preserving its mechanical strength when pore sealing pretreatment was applied.
AB - Underfill materials had been widely employed in the flipchip packaging to fill the gaps of solder bumps connecting IC chip and organic substrate in order to prevent failure of the solder joints. For radio-frequency (RF) device applications, underfill materials should possess low dielectric constant to alleviate power loss at high-frequency, in addition to good thermal and mechanical properties. In this study, a novel approach of incorporating porosity through porous silica filler was attempted to develop low-k underfill materials. An inorganic, sacrificial material, hexamethylcyclotrisiloxane (D3), was used to temporarily seal the interconnected pores in the porous silica at temperature < 95°C by thermal and solvent pretreatment methods, and was later removed thermally at 125-165°C during the crosslinking reaction of underfill materials. For underfill materials with 15% filler content, a 7.8% reduction in dielectric constant has been successfully demonstrated and achieved by pore sealing of porous silica (60% porosity) using solvent pretreatment, while maintaining the mechanical strength of porous silica, 2.6 GPa. Moreover, the adhesion between epoxy and porous silica in the underfull materials was found to critical in preserving its mechanical strength when pore sealing pretreatment was applied.
UR - http://www.scopus.com/inward/record.url?scp=52649106968&partnerID=8YFLogxK
U2 - 10.1109/ICEPT.2008.4607043
DO - 10.1109/ICEPT.2008.4607043
M3 - Conference contribution
AN - SCOPUS:52649106968
SN - 9781424427406
T3 - Proceedings, 2008 International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2008
BT - Proceedings, 2008 International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2008
Y2 - 28 July 2008 through 31 July 2008
ER -