A laser direct-writing magnetic integration process: Low-temperature packaging of magnetic films on on-chip inductive components

The integration of functional magnetic films into chips can effectively solve the problem of large area and low performance of radio frequency (RF) on-chip inductive components. However, the lack of low-temperature integration processes compatible with standard semiconductor processes for magnetic films hinders the practical application of on-chip inductive components with magnetic films. In this study, to improve the performance of on-chip inductive components, a laser direct-writing process is proposed for the first time for low-temperature packaging of magnetic films on on-chip inductive components. In this process, an oriented laser is used to heat and solidify a magnetic slurry film composed of thermosetting resin and magnetic nanoparticles, which is coated on on-chip inductive component, thus realizing the low-temperature integration of magnetic film on on-chip component. Furthermore, the laser direct-writing process is applied to integrate ferroferric oxide (Fe₃O₄) magnetic film onto a meander on-chip inductor. Compared to the same type of air-core meander inductor, the inductance (L) and quality factor (Q) of the meander inductor with Fe₃O₄ magnetic film are increased by 20.2 % and 7 % at 1 GHz, respectively. The results indicate that the laser direct-writing magnetic integration process is simple, low-temperature, efficient, and fully compatible with standard semiconductor process, and has great application prospects in magnetic material integration of on-chip inductive components.