Method of making a multilayer electrical coil

A thin film additive method of fabricating a multi-planar-coil winding for an inductive component, comprising the steps of

• patterning a first insulating film layer with a continuous spiral planar channel, and a plurality of outer apertures outside said spiral, the inner end of said spiral channel terminating at a first one of a predetermined plurality of inner locations distributed about a central section of said layer, the outer end of said spiral channel terminating at a first one of said outer apertures,
• plating the channel and apertures of said first layer full of conductive metal to form a first coil,
• bonding a second thin film insulating layer over said first layer,
• forming in said second insulating layer, a plurality of outer apertures in registration with the outer apertures of the first insulating layer, and a single inner aperture at said first location in registration with the inner end of the conductive spiral defined in said first insulating layer,
• plating the apertures in said second layer full of conductive metal,
• bonding a third thin film insulating layer over said second layer,
• patterning said third insulating layer with a second planar spiral channel having an inner end terminating in registration with said inner aperture in said second insulating layer and a plurality of out apertures in registration with the outer apertures in said first and second insulating layers, the outer end of said spiral channel terminating at a second one of said outer apertures,
• plating said apertures and channel in said third layer full of conductive metal to form a second coil,
• bonding a fourth insulating layer over said third layer,
• patterning said fourth insulating layer with a plurality of outer apertures in registration with the outer apertures of the underlying layers,
• plating the apertures in said fourth layer full of conductive metal,
• bonding a fifth thin film insulating layer over said fourth insulating layer,
• patterning said fifth insulating layer with a plurality of outer apertures in registration with the outer apertures of the underlying layers and a spiral channel having an outer end terminating at said second location of said outer apertures and an inner end terminating at a second one of said predetermined inner locations about the corresponding central section,
• plating the channel and apertures of said fifth layer to form a third coil,
• bonding a sixth thin film insulating layer over the fifth insulating layer,
• patterning said sixth insulating layer with a plurality of outer apertures in registration with the outer apertures of the underlying layers and an inner aperture at said second location,
• plating the apertures of said sixth layer with solid conductive metal,
• bonding a seventh thin film insulating layer on top of said sixth thin film insulating layer,
• patterning said seventh thin film insulating layer with a plurality of outer apertures in registration with the outer apertures of the underlying layers, a spiral channel having an outer end terminating at a third location of one of said outer apertures and an inner end terminating at said second location,
• plating the channel and apertures of said seventh layer full of conductive metal to form a fourth coil,
• whereby, a monolithic thin film multi-planar-coil winding is formed with the outer ends of each planar coil being connected to solid metal plated posts extending through the layers.