Method of forming a three-dimensional integrated inductor

A method of forming an integrated transformer, comprising the steps of:

• forming at least two electrically independent but physically intertwined multi-turn coils by:
• providing a semiconductor substrate;
• forming the bottoms of each of the at least two multi-turn coils by:
• depositing, over the semiconductor substrate, a first photoresist layer and forming a trench therein;
• filling the trench with electroplated metal, the first photoresist layer and electroplated trench forming-a first layer;
• forming the sides of each of the at least two multi-turn coils by:
• depositing, over the first layer, a second photoresist layer and forming first and second trenches therein;
• filling the first and second trenches with electroplated metal, the second photoresist layer and first and second electroplated trenches forming a second layer;
• forming the tops of each of the at least two multi-turn coils by:
• depositing, over the second layer, a third photoresist layer and forming a trench therein;
• filling the trench of the third photoresist layer with electroplated metal thereby forming a third layer;
• and
• removing the first, second, and third photoresist layers to expose the at least two multi-turn coils.

A method of forming an integrated inductor, comprising:

• providing a semiconductor substrate;
• depositing a passivation layer over the substrate;
• depositing a first sputtered metal layer onto the dielectric layer thereby forming a barrier layer;
• depositing a second sputtered metal layer onto the first sputtered metal layer, the second sputtered metal layer adhering to the first sputtered metal layer;
• depositing a first photoresist layer onto the second sputtered metal layer;
• forming a first trench within the first photoresist layer so as to expose a top portion of the second sputtered metal layer;
• depositing a first plated metal layer within the first trench, the first photoresist layer and the first plated metal layer providing a first layer of the inductor;
• depositing a second photoresist layer over the first layer of the inductor;
• forming first and second trenches within the second photoresist layer, the first and second trenches each exposing a top portion of the first plated metal layer;
• depositing a second plated metal layer within each of the first and second trenches of the second photoresist layer, the second photoresist layer and first and second plated trenches formed therein providing a second layer of the inductor;
• depositing a third sputtered metal layer over the second layer of the inductor;
• depositing a third photoresist layer over the third sputtered metal layer;
• forming a trench within the third photoresist layer;
• depositing a third plated metal layer within the trench of the third photoresist layer, the third photoresist layer and the third plated metal layer providing a third layer of the inductor;
• and
• etching the first, second, and third photoresist layers and the first, second, and third sputtered metal layers to expose the first, second, and third plated metal layers to expose a multi-turn coil.