Thin-film decoupling capacitors for multi-chip modules

Thin-film decoupling capacitors based on ferroelectric lead lanthanum zirconate titanate (PLZT) films are being developed for use in advanced packages, such as multi-chip modules. These thin-film decoupling capacitors are intended to replace multi-layer ceramic capacitors for certain applications, since they can be more fully integrated into the packaging architecture. The increased integration that can be achieved should lead to decreased package volume and improved high-speed performance, due to a decrease in interconnect inductance. PLZT films are fabricated by spin coating using metal carboxylate/alkoxide solutions. These films exhibit very high dielectric constants (ε⩾900), low dielectric losses (tanδ≈0.01), excellent insulation resistances (ρ>10¹³ Ω-cm at 125°C), and good breakdown field strengths (E_B≈900 kV/cm). For integrated circuit applications, the PLZT dielectric is less than 1 μm thick, which results in a large capacitance/area (8-9 nF/mm ²). The thin-film geometry and processing conditions also make these capacitors suitable for direct incorporation onto integrated circuits and for packages that require embedded components