Patent ID: 7047625

Claim:
A planarizing process comprising: providing a first layer of a material having an upper surface; etching in said first layer a cavity having a floor; forming on said cavity floor a copper coil, having at least 5 turns and a DC resistance that is less than about 3 ohms; applying a layer of photoresist to a thickness that is more than sufficient to cover said coil; hard baking said layer of photoresist and then planarizing so that between about 1.5 and 2 microns of remaining hard baked photoresist extends above said upper surface; coating said layer of baked photoresist with a layer of alumina; and then planarizing by means of chemical mechanical polishing until said coil is just exposed and no photoresist remains on said upper surface, said layer of alumina serving to stabilize said baked photoresist layer whereby said baked photoresist layer does not delaminate as said upper surface is approached and termination of planarization is facilitated.