Performance enhanced copper core BGA

The copper core BGA (C/sup 2/BGA) is a copper core, face up multilayer BGA package. It is designed for high performance, high density applications. Very low inductance and low impedance solid copper vias are used to connect the traces on either side of the copper core. These solid copper vias are defined using a proprietary microisland via (MIVia) technology. A brief description of the microisland via manufacturing process is also discussed. The ease with which the copper core can be grounded using these low impedance solid copper vias allows the designers to define a multitude of stripline and microstrip line structures with well defined and well controlled impedances. This paper discusses some of the electrical performance results of microisland via and compares it with plated through via. The C/sup 2/BGA thermal performance is also improved over conventional face-up packages due to the use of the copper core and is comparable to the thermally enhanced cavity down package. Thermal modeling and measurement data are presented and some guidelines to enhance thermal performance are discussed. Finally, reliability data for the microisland via stack-up in the C/sup 2/BGA is presented.