Thin Films of Embedded Capacitors for Multichip Modules and Printed Circuit Boards

摘要

Utilizing THE Combustion Chemical Vapor Deposition (CCVD) process, submicron dielectric films were deposited on copper foils and platinum-coated silicon wafers for embedded capacitors to be incorporated in multichip modules (MCM) and printed circuit boards (PCB) for higher packaging density and better electronic performance. Critical CCVD processing parameters influencing microstructure and phase formation were studied. Electronic, chemical, and physical properties were characterized. For CCVD dielectrics-coated silicon wafers, less than 2precent variation in thickness and, correspondingly, capacitance was observed. Capacitance density ranged from 23 to 331 nF/cm~2, leakage current density as low as 1 nA/cm~2, measured at 0.5 MV/cm, and breakdown field of 2.11-5.44 MV/cm were achieved for multichip modules. For PCB applications, the yield of silica capacitors on copper foils was improved from 83-90precent to 97precent by reducing copper foil surface roughness. The capacitance density was in the range of 37-109 nF/cm~2; breakdown voltage was approx2.5 MV/cm while leakage current density was approx10~(-7) A/cm~2 at 10V. The as-deposited specimens on copper exhibited peel strength up to 3.7 lb/in, while shear stress tests of the asdeposited SiO_2 specimens showed a shear strength over 373 lb/in~2. These results and related corrosion resistance studies showed very promising potential of the CCVD thin films for embedded capacitors.