Substrate with Combined Embedded Capacitance and Resistance for Better Electrical Performance and Higher Integration
Many articles have been published on the benefit of thin substrates for use as embedded capacitor layers as well as thin film
resistive material for embedded resistors. Until now the utilization of both technologies within a printed circuit design
required the use of separate cores within the PCB. This adds additional thickness to the PCB as well as cost. A new
substrate has been developed to address these issues.
Embedded technologies improve the electrical performance of high speed digital circuits as well as enabling the removal of
SMT discrete components (the ratio of passives to active components is increasing while the available board surface area is
decreasing). By combining capacitance and resistance on the same core,with the resistor foil being supplied on one or both
sides of the capacitor dielectric,these benefits can be realized without increasing the overall number of layers or the substrate
thickness. Also,some unique R-C circuit designs can be formed by utilizing this substrate.
We will discuss the process and design guidelines for using this substrate as well as some possible applications. Also,results
from high frequency testing of PCB test vehicles will be discussed. Future product developments will also be shared.
It will be demonstrated that this new substrate has excellent electrical properties while being able to be readily manufactured
using typical inner-layer processing.