| Liquid crystal polymer (LCP) was introduced as a unique material to address significant challenges existing with concurrent substrate material. Predicted improvements would be on reduced tangent loess of 0.0025 at higher frequencies, reduced dielectric constant of the material, lower moisture absorption coefficient of 0.04%, and lower process temperature of 335 °C. Apart from the introduction of new material a novel conceptual design of using multilayered LCP to serve both the purpose of MEMS die carrier substrate and sealed cap layer was investigated.;Micro mechanical punched vias were introduced in this research instead of more common micro via fabrication techniques like laser drilling, e-beam machining, and plasma etching. An in depth study of micro via fabrication was addressed with via diameters in between 50 to 100 microm and with different via pitches from 75 to 225 microm. LCP and copper burrs are formed as a result of micro mechanical punching would prevent uniform via filling during metallization process, lamination, and reliability.;A sequential wet chemical etching process of oxidation, etching, and neutralization was introduced in this research to eliminate the burrs, but does not prevent the formation. Experiments were designed to examine the treatment time as a factor on LCP and copper burrs removal. Experiments were designed to correlate the LCP via wall roughness with the variation of oxidation, etching, and neutralization treatment times. The via wall roughness could have an impact on adhesion of via metallization to the LCP sidewall, but was not evaluated in this work.;The carbonated LCP debris left around the via edge was removed by oxygen plasma cleaning. Power and pressure were varied in the oxygen plasma generation to see the effect on the vias roughness.;DC and reverse pulse plating (RPP) were examined for the metallization process in order to evaluate these two electroplating processes relative to thickness uniformity, surface roughness, and sidewall coverage. Daisy chain and Kelvin structure test were fabricated to evaluate the electrical performance of the electroplated vias. |
