Process for high voltage superjunction termination

A method of manufacturing a semiconductor device having an active region and a termination region surrounding the active region, the method comprising:

• providing a semiconductor substrate having first and second main surfaces opposite to each other, the semiconductor substrate having a heavily doped region of a first conductivity type at the second main surface and having a lightly doped region of the first conductivity type at the first main surface;
• forming a trench in the termination region, the trench extending from the first main surface toward the heavily doped region to a first depth position, the trench being greater than 20 micrometers wide;
• filling the trench in the termination region with an oxide material;
• and
• prior to forming the trench in the termination region, forming columns of the first conductivity type and a second conductivity type in the active region, the second conductivity type being opposite to the first conductivity type, the columns extending from the first main surface toward the heavily doped region to a third depth position.