The invention relates to a preparation method of an on-
chip magnetic core power
inductor. The preparation method comprises the following steps:
etching a
silicon groove of an
inductor end winding and a
silicon groove of an
inductor middle winding on the upper surface of a
wafer by utilizing photoetching and
deep reactive ion etching; forming an insulating film layer, a
titanium barrier layer and a
copper seed crystal layer on the groove walls of the inductor end winding
silicon groove and the inductor middle winding silicon groove in sequence;
copper is fully plated in the inductor end winding silicon groove and the inductor middle winding silicon groove through
electroplating; carrying out photoetching and
deep reactive ion etching on bulk silicon at the peripheries of the upper ends of the inductor end winding silicon groove and the inductor middle winding silicon groove on the upper surface of the
wafer, and
coating a fluid magnetic material formed by fusing soft
magnetic powder and
epoxy resin to form a part of
magnetic core;
polishing the lower surface of the
wafer by adopting a CMP (Chemical Mechanical
Polishing) process until the lower end of the inductor end winding is exposed, and forming a
welding spot at the exposed part of the lower end of the inductor end winding; carrying out photoetching and
deep reactive ion etching on bulk silicon at the peripheries of the lower ends of the inductor end winding silicon groove and the inductor middle winding silicon groove on the lower surface of the wafer, and
coating a fluid magnetic material formed by fusing soft
magnetic powder and
epoxy resin to form the other part of
magnetic core; and
polishing the lower surface of the magnetic core by adopting a CMP (Chemical Mechanical
Polishing) process to
expose welding spots of the end winding of the inductor to obtain the prepared on-
chip magnetic core power inductor. The problems that a traditional inductor is large in size, high in material cost and incompatible with the
CMOS technology, and a
chip-level fully-integrated power supply product with high integrated packaging efficiency cannot be achieved are solved.