Semiconductor device and method of manufacturing semiconductor device

A method of manufacturing a semiconductor device having an active region through which current flows;

• and a termination structure region arranged outside the active region, the termination structure region having a breakdown voltage structure surrounding a periphery of the active region, the method comprising:
• forming a first semiconductor layer of a first conductivity type on a front surface of a semiconductor substrate of the first conductivity type, the first semiconductor layer having an impurity concentration lower than an impurity concentration of the semiconductor substrate;
• forming a lower parallel pn structure at an upper surface of the first semiconductor layer, the lower parallel pn structure having in a plane parallel to the front surface, a plurality of lower first columns of the first conductivity type and a plurality of lower second columns of a second conductivity type, the lower first columns being arranged alternately with the lower second columns;
• forming a center parallel pn structure on an upper surface of the lower parallel pn structure, the center parallel pn structure having in a plane parallel to the front surface, a plurality of center first columns of the first conductivity type and a plurality of first rings of the second conductivity type arranged surrounding the active region and alternating with the center first columns;
• forming an upper parallel pn structure on an upper surface of the center parallel pn structure, the upper parallel pn structure having in a plane parallel to the front surface, a plurality of upper first columns of the first conductivity type and a plurality of upper second columns of the second conductivity type, the upper first columns being arranged alternately with the upper second columns;
• and
• forming an uppermost parallel pn structure on an upper side of the upper parallel pn structure, the uppermost parallel pn structure having in a plane parallel to the front surface, a plurality of uppermost first columns of the first conductivity type and a plurality of second rings of the second conductivity type arranged surrounding the active region and alternating with the uppermost first columns, wherein
• said forming a center parallel pn structure includes
• forming each of the first rings to have a width greater than a width of each of the lower second columns, and
• forming an interval between an adjacent two of the first rings to be greater than an interval between an adjacent two of the lower second columns, and said forming an uppermost parallel pn structure includes
• forming each of the first and second rings to have a same width,
• forming an interval between an adjacent two of the second rings to be equal to the interval between the adjacent two of the first rings, and
• forming the second rings to be nonoverlapping with the first rings in a plan view.