Integrated circuit with an embedded inductor or transformer

A transformer, comprising:

• a first integrated circuit with at least one first embedded transformer coil with first coil windings and first coil spaces lying in a first plane oriented in a first direction and with a first trench oriented in a second direction at an angle to the first direction and filled with replacement dielectric, the first trench extending from a first surface of a first semiconductor substrate to a first depth in the first semiconductor substrate, the first semiconductor substrate having a second surface opposite the first surface;
• a second integrated circuit with at least one second embedded transformer coil with second coil windings and second coil spaces lying in a second plane oriented in the first direction and with a second trench oriented in the second direction at an angle to the first direction and filled with replacement dielectric, the second trench extending from a first surface of a second semiconductor substrate to a second depth in the second semiconductor substrate, the second semiconductor substrate having a second surface opposite the first surface of the second semiconductor substrate;
• the second integrated circuit inverted and bonded to the first surface of the first integrated circuit using a dielectric bonding material;
• a center of the second transformer coil aligned with a center of the first transformer coil;
• a layer of magnetic core material surrounded by a dielectric bonded between the first integrated circuit and the second integrated circuit and disposed between the first transformer coil and the second transformer coil.