Glass-Passivated Thick-Film Capacitors for RC Circuits

The advantages, disadvantages, and the reasons for the limited usage of thick-film capacitors are discussed. The electrical and environmental properties of a glass-passivated high dielectric constant (HiK) (~1000) capacitor which does not require hermetic packaging are described. Design criteria for achieving a Iow-cost thick-film capacitor-resistor-conductor network are presented. These include: 1) satisfying multiple circuit requirements; 2) using many capacitors, resistors, and conductors per circuit or per processing operation; 3) using Iow-cost materials, sealing techniques, and processes; 4) achieving high yields. An example is cited of a television tuner circuit on a 2 X 3 X 0.040-in substrate utilizing 47 resistors, 30 capacitors, 8 crossovers, and 1 ground plane in which the substrate also serves as a printed,circuit board for mounted discrete components.