Method of manufacturing an embedded magnetic component device
A magnetic core is situated in a cavity routed into an insulating substrate. The and magnetic core are covered with a first insulating layer. Through holes are then formed through the first insulating layer and the insulating substrate, and plated to form conductive vias. Metallic traces are added to the exterior surfaces of the first insulating layer and the insulating substrate to form upper and lower winding layers. The metallic traces and conductive vias define the respective primary and secondary side windings for an embedded transformer. At least a second set of the outer conductive vias, are spaced farther from the cavity than a first set, and have greater via hole diameter than the vias in the first set. This reduces the resistance of the windings for a given substrate size and improves the performance of the device.
1. A method of manufacturing an embedded magnetic component device, comprising:
a) preparing an insulating substrate including a first side and a second side opposite the first side, and including a toroidal cavity therein, the toroidal cavity including an inner and an outer periphery;
b) installing a magnetic core in the toroidal cavity;
c) forming an electrical winding that extends through the insulating substrate and around the magnetic core, the electrical winding including:
upper conductive traces located on the first side of the insulating substrate;
lower conductive traces located on the second side of the insulating substrate;
inner conductive connectors extending through the insulating substrate adjacent to the inner periphery of the magnetic core, the inner conductive connectors respectively defining electrical connections between respective upper conductive traces and respective lower conductive traces; and
outer conductive connectors extending through the insulating substrate adjacent to the outer periphery of the magnetic core, the outer conductive connectors respectively defining electrical connections between respective first upper conductive traces and respective first lower conductive traces; and
d) in step c) forming the outer conductive connectors to include a first set of outer conductive connectors and a second set of outer conductive connectors; wherein
the first set of outer conductive connectors are located along the outer periphery of the toroidal cavity and are spaced from the outer periphery of the toroidal cavity by a first distance; and
the second set of the outer conductive connectors are located adjacently without the first set of outer conductive connectors in between and at a greater distance from the outer periphery of the toroidal cavity than the first set of outer conductive connectors;
each one of the first and second set of outer conductive connectors is electrically connected to one of the inner conductive connectors through one of the upper conductive traces or one of the lower conductive traces;
two outer conductive connectors of the second set of outer conductive connectors are located directly adjacent to respective ones of the first set of outer conductive connectors;
in a thickness direction of the insulating substrate, either:
the upper conductive traces connected to the first set of outer conductive connectors do not overlap with the upper conductive traces connected to the second set of outer conductive connectors; or
the lower conductive traces connected to the first set of outer conductive connectors do not overlap with the lower conductive traces connected to the second set of outer conductive connectors; and
adjacent inner conductive connectors connected to the second set of the outer conductive connectors are located at different distances from the cavity.
2. The method of claim 1 , wherein:
the upper conductive traces connected to the first set of outer conductive connectors are provided at a same layer as the upper conductive traces connected to the second set of outer conductive connectors; or
the lower conductive traces connected to the first set of outer conductive connectors are provided at a same layer as the lower conductive traces connected to the second set of outer conductive connectors.
3. The method of claim 1 , wherein the first set of outer conductive connectors and second set of outer conductive connectors are provided in separate regions of the substrate.
4. The method of claim 1 , wherein outer conductive connectors in the second set of outer conductive connectors have a greater cross-sectional area than outer conductive connectors in the first set of outer conductive connectors.
5. The method of claim 1 , further comprising mounting electronic components on the first side and/or the second side of the insulating substrate.
6. The method of claim 1 , wherein:
the magnetic core includes a first section and a second section;
the electrical winding includes a primary electrical winding disposed around the first section and a secondary electrical winding disposed around the second section; and,
the primary electrical winding and the secondary electrical winding are isolated from one another, and the primary electrical winding and the secondary electrical winding respectively include the upper conductive traces, the lower conductive traces, the inner conductive connectors, and the outer conductive connectors.
7. The method of claim 1 , further comprising:
forming a first isolation barrier on the first side of the insulating substrate, covering at least the portion of the first side between the primary electrical winding and the second electrical winding where the primary electrical winding and the second electrical winding are closest, the first insulation barrier defining a solid bonded joint with the first side of the insulating substrate; and
forming a second isolation barrier on the second side of the insulating substrate, covering at least a portion of the second side between the primary electrical winding and the second electrical winding, where the primary electrical winding and the second electrical winding are closest, the second isolation barrier defining a solid bonded joint with the second side of the insulating substrate.