Abstract
Phenolic resins have been widely used as hardeners for epoxy molding compounds in electronic applications, because of their good thermal, mechanical, and electronic properties. Conventional phenolic resins such as phenol novolac, however, often cannot meet the strict requirements in advanced microelectronic applications. Therefore developments of high performance phenolic hardeners are required. Incorporation of poly-nuclear aromatic structure, such as a naphthalene skeleton, into a resin backbone was investigated. The naphthalene-containing resin had lower viscosity in comparison with benzene ring based one at a same softening point.
It was also shown that naphthalene based resin had higher glass transition temperature (Tg) in a thermoplastic stage, and that cured polymers obtained from the naphthalene based resins had higher Tg than those from benzene based ones, in addition to lower moisture absorption and thermal expansion. Moreover, the naphthalene based resins showed excellent thermal stabilities, which seemed to cause the resins to have higher flame-retarding properties.
