Coil inductor

A semiconductor device comprising an inductor, wherein said semiconductor device comprises:

• a first dielectric layer made of a first dielectric material;
• a second dielectric layer made of a second dielectric material different from said first dielectric material and embedded in said first dielectric layer;
• and
• a trench filled with a conductive material and formed in said second dielectric layer and representing at least a part of an inductor coil of said inductor.

A method of forming a semiconductor device comprising an inductor, comprising the steps of:

• forming a dielectric layer over or as part of a metallization layer;
• performing a two-step etching process of said dielectric layer comprising:
• performing a first etching step to form a first trench with a first depth in said dielectric layer;
• performing a second etching step to form a second trench with a second depth in said dielectric layer and to further etch said first trench to increase said first depth of said first trench to a third depth deeper than said second depth;
• and
• filling said first trench with said third depth with a conductive material to form an inductor coil.