Integrated high voltage capacitor having capacitance uniformity structures and a method of manufacture therefor

A method of forming an integrated circuit including a transistor and a capacitor, comprising:

• forming a first doped well region in a transistor region and a second doped well region in a capacitor region of a semiconductor substrate using first shared processing steps, the second doped well region defining a first capacitor plate;
• forming a field oxide layer over the second doped well region;
• forming a gate structure for the transistor over the first doped well region;
• forming a first interlevel dielectric layer over the field oxide layer and over the gate structure;
• forming a conductive lead above the first interlevel dielectric layer to provide an electrical connection for the transistor;
• forming a second interlevel dielectric layer over the first interlevel dielectric layer including over the conductive lead;
• forming a protective overcoat layer over the second interlevel dielectric;
• forming an opening through the protective overcoat and the second interlevel layer down to the conductive lead, using at least two photomask patterning and etching steps;
• and
• forming a second capacitor plate over the protective overcoat layer over the second doped well region, and forming a conductive feature over the protective overcoat layer and within the opening in the transistor region using second shared processing steps.