examples of saturated straight chain alkyl moieties u2014 ch 2 ch u2550 chch 3 is an example of an olefin or unsaturated alkyl moiety an example of a monocyclic aliphatic saturated hydrocarbon moiety is cyclohexane an example of a substituted alkyl moiety is a moiety wherein for example a hydrogen atom is replaced with an inert atom an aryl may denote an aromatic ring a substituted aromatic ring and fused aromatic rings phenyl hydroxyphenyl and napthalene are examples of aryl moieties with respect to an underfill formulation or a molding compound a composition such as a siloxane based aromatic diamine may be combined with an epoxy in circuit packaging processes epoxies are favored reasons for the popularity of an epoxy as a component of an underfill formulation or molding compound include the versatility of epoxy and tuning the properties of the overall formulation or compound good adhesion to various substrates low cure shrinkage good electrical properties compatibility with many materials and the ability of an epoxy to cure under a wide variety of conditions bisphenol a bisphenol f or napthalene based epoxy resins are suitable materials for underfill formulations and or molding compounds an embodiment of a molding compound includes but is not limited to an epoxy system including an epoxy e g bisphenol a bisphenol f nathalene a siloxane based aromatic diamine and a filler suitable fillers include but are not limited to ceramics such as silica alumina etc representative siloxane based aromatic diamines include but are not limited to the following where r 3 r 4 r 5 and r 6 are independently selected from h methyl ethyl propyl etc moieties and where r 3 r 4.