Method of making low profile pin-less planar magnetic devices

A method of manufacturing a pin-less, surface mountable planar transformer from at least one subassembly, comprising the steps of:

• forming at least one subassembly by:
• a. providing a plurality of insulative layers each having a predetermined number of conductive coil turns, a termination pad conductively connected to each of said conductive coil turns, and an alignment marking supported on a surface thereof;
• b. stacking the plurality of insulative layers;
• c. aligning the stacked layers using the alignment markings;
• d. laminating the stacked layers to form a monolithic subassembly structure;
• e. drilling vias through the monolithic subassembly structure;
• and
• f. plating the vias to selectively interconnect each of said conductive coil turns of predetermined ones of said plurality of insulative layers of said monolithic subassembly structure;
• stacking the subassembly with at least one of another subassembly and an insulative layer to form a stacked assembly, the insulative layer including a predetermined number of conductive coil turns, a termination pad conductively connected to each of said conductive coil turns, and an alignment marking supported on a surface thereof;
• aligning the stacked assembly using the alignment markings;
• laminating the stacked assembly to form a monolithic assembly;
• drilling vias through the monolithic assembly;
• routing an aperture in the monolithic assembly sized to receive a ferrite core, and routing a portion of an edge of the monolithic assembly to expose the termination pad of at least one of the plurality of insulative layers;
• masking the routed monolithic structure;
• plating the vias to selectively interconnect each of said conductive coil turns of predetermined ones of said plurality of insulative layers of the monolithic assembly and to form pin-less terminations at the exposed termination pads;
• and
• providing a magnetically permeable core within the aperture.

A method of manufacturing a pin-less, surface mountable planar magnetic device, comprising the steps of:

• a. providing a plurality of insulative layers each having a predetermined number of conductive coil turns, a termination pad conductively connected to each of said conductive coil turns, and an alignment marking supported on a surface thereof, the coil turns and termination pad being formed by applying photoresist to the conductive material, masking the photoresist with a desired layer pattern, exposing at least a portion of the photoresist, etching the photoresist to obtain the desired layer pattern, and rinsing the layer clean of residue;
• b. stacking the plurality of insulative layers;
• c. aligning the stacked layers using the alignment markings;
• d. laminating the stacked layers to form a monolithic structure;
• e. drilling vias through the monolithic structure;
• f. routing an aperture in the monolithic structure sized to receive a ferrite core, and routing a portion of an edge of the monolithic structure to expose the termination pad of at least one of the plurality of insulative layers;
• g. masking the routed monolithic structure;
• and
• h. plating the vias to selectively interconnect each of said conductive coil turns of predetermined ones of said plurality of insulative layers and to form pin-less terminations at the exposed termination pads.

A method of manufacturing a pin-less, surface mountable planar magnetic device, comprising the steps of:

• a. providing at least one insulative substrate having conductive material on at least one side thereof and an alignment marking;
• b. applying photoresist to the conductive material;
• c. masking the photoresist with a desired layer pattern, the desired layer pattern including a predetermined number of conductive coil turns and a termination pad conductively connected to each of said conductive coil turns;
• d. exposing the photoresist;
• e. etching the photoresist to obtain the desired layer pattern on the insulative substrate;
• f. rinsing the etched layer pattern clean of residue;
• g. repeating steps a-f for each desired layer pattern in order to obtain a series of desired layer patterns for stacking;
• h. stacking the plurality of insulative layers;
• i. aligning the stacked layers using the alignment markings;
• j. laminating the stacked layers to form a monolithic structure;
• k. drilling vias through the monolithic structure;
• l. routing an aperture in the monolithic structure sized to receive a ferrite core, and routing a portion of an edge of the monolithic structure to expose the termination pad of at least one of the plurality of insulative layers;
• m. masking the routed monolithic structure;
• and
• n. plating the vias to selectively interconnect each of said conductive coil turns of predetermined ones of said plurality of insulative layers and to form pin-less terminations at the exposed termination pads.

A method of manufacturing a pin-less, surface mountable planar transformer, comprising the steps of:

• a. providing a plurality of insulative layers each having a predetermined number of conductive coil turns, a termination pad conductively connected to each of said conductive coil turns and an alignment marking supported on a surface thereof;
• b. drilling vias through each of the insulative layers;
• c. routing an aperture in each of the insulative layers sized to receive a magnetically permeable core, and routing a portion of an edge of the each of the insulative layers to expose the termination pad of each of the insulative layers;
• d. stacking the plurality of insulative layers;
• e. aligning the stacked layers using the alignment markings;
• f. laminating the stacked layers to form a monolithic structure;
• g. masking the routed insulative layers;
• h. plating the vias to selectively interconnect each of said conductive coil turns of predetermined ones of said plurality of insulative layers and to form pin-less terminations at the exposed termination pads;
• and
• i. providing a magnetically permeable core within each of said apertures.