As CPUs increase in performance, the numbers of passive components on the surface of the boards are increasing dramatically. To reduce the number of components, as well as improve the electrical performance (i.e. reduce inductance), designers are increasingly embedding capacitive layers in the Printed Circuit Board (PCB).
The majority of the products in use today utilize reinforced epoxy laminates. These products are relatively easy to handle and provide good electrical performance, but a need exists for even better performance than a fiberglass-reinforced product can produce.
Other materials are being developed that are thinner (and thus increase capacitance and reduce inductance), but either have problems with dielectric breakdown strength, handling or only marginal improvements over the reinforced epoxy material. A need exists for an ultra-thin (less than 25 micron) material that not only provides improved electrical performance, but can be readily manufactured using standard PCB processing.
We will discuss the design criteria we used for developing our family of products, as well as the results. The design of the conductor (copper foil) has been determined to be as critical as the properties of the dielectric (polymer). Examination of the effect of loading the polymer with High Dk ferroelectric particles will also be examined.
The products have been through both internal and external testing and are compared to existing and developing capacitor materials. We will describe the electrical as well as the processing characteristics in detail, and how these types of products can greatly improve performance of high-speed systems