Build-up Electrical Insulation Material with Low-Dielectric Loss Tangent, Low-CTE and Low-Surface Roughness

With the increasing speed of information and communication equipments in recent years, together with the high-speed signal processing of LSIs, there is a requirement for build-up electrical insulation materials (used in IC package substrates) to have low-dielectric loss tangent which reduces dielectric loss so as to achieve low transmission loss in the high-frequency GHz bands. At the same time, there is an increasing need for materials to have low-CTEs (Coefficient of Thermal Expansion) so as to ensure highly reliable substrates. With ou formulation technology, we have developed a next-generation film-shaped build-up electrical insulation material compatible with high-frequency signal transmission by using a composition of practical thermosetting epoxy resin, which has realized both a low-dielectric loss tangent and at the same time, a low-CTE. In addition, this material can show a low-surface roughness after the film desmear process. It is thus expected to help reduce not only dielectric loss by means of a low-dielectric loss tangent, but also conductor loss caused by the skin effect, and will promote fine line formation by means of SAP (Semi Additive Process).