An Improved Laminate for Embedded Capacitance Applications

The industry trend to smaller feature sizes and device miniaturization is making the use of embedded passive devices more attractive. This paper describes a recent advance in the fabrication and use of an epoxy-glass fabric laminate for embedded capacitance applications. The key performance enhancements in the buried capacitance laminate are precise thickness tolerance, improved dimensional consistency, and reduced levels of electrical breakdown during hipot testing. The use of a square-weave glass fabric with tight resin content control yields a laminate with a very precise thickness and improved dimensional consistency. A laminate with reduced levels of dielectric breakdown during a 500V DC test (hipot test) can be fabricated using a carefully controlled manufacturing process. The enhanced square-weave glass fabric also exhibits excellent resistance to Conductive Anodic Filament (CAF) growth during 1000 hour temperature/humidity aging under 100V DC bias.