Fabrication of 2D and 3D inductors for DC-DC converters integrated on glass interposer

Abstract

Inductors are a key component for voltage regulators and its on-chip integration could significantly improve their performance and scalability capabilities. However, innovative microfabrication processes have yet to be developed in order to miniaturise the inductors while maintaining their overall performance. In that regards, thin-film magnetic materials on glass substrates, which amplifies inductance values, should ease on-chip inductor integration. Using Ni45Fe55 and Co80P20 magnetic materials, we successfully fabricated 2D core and coreless copper inductors, on both glass and silicon substrates for comparison purposes. Inductors on glass exhibit better performance than the ones fabricated on silicon. An inductance of 10.3 nH (14.7 nH/mm2) at 100 MHz and a quality factor of 5 were reached. We also propose a process flow and morphological characterizations of a 3D inductor architecture on glass substrate featuring through glass vias.