Abstract
High performance integrated passives, such as capacitors and inductors, are in increasingly higher demand in modern wireless systems. Much effort has been focused on developing single chip module using air-core inductors and capacitors with low-dielectric constant films. However, at present this technology has a number of limitations for designing passives of large inductance and capacitance values on restricted semiconductor substrate area. Technologies of high performance magnetic and dielectric films and integration processes are essential for the purpose of reducing manufacturing cost, size, weight, and improve performance and battery life of modern communications products. In this paper we present an overview of thin film passives and their integration processes with special focus on the thin film inductors with high-frequency magnetic thin films. In order to realize an excellent permeability-frequency response, larger values of saturation magnetization and anisotropy field are required while keeping the film thickness less than skin depth. Microstructure control is the effective technique for adjusting the properties of magnetic thin films. The terminated columnar structure of Fe-C layer with CoZrNb amorphous layer, discontinuous structure of multilayer films with layers less than 2 nm thickness, and inclined grain growth of CoFe-Al2O3 composite films are introduced as examples.
