The present invention relates to semiconductor devices and their manufacture, and more specifically to a structure and method of making a stacked transformer structure using through-silicon vias (TSVs).
A transformer is a device that transfers electrical energy from one circuit to another through inductively coupled conductors or coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer and thus a varying magnetic field through a second or secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or “voltage”, in the secondary winding. This effect is referred to as inductive coupling.
Transformers range in size from on-chip transformers occupying the area less than one square millimeter to huge units weighing hundreds of tons used to interconnect portions of power grids. However, regardless of size, all transformers operate on the same basic principles, although the range of designs is wide. While new technologies have eliminated the need for transformers in some electronic circuits, transformers are still found in nearly all electronic devices.