Method of fabricating semiconductor memory having a second active region disposed at an outer side of a first active region

A method of forming a semiconductor memory device, comprising;

• providing a substrate;
• forming an active structure in the substrate, the active structure comprising:
• a first active region comprising a plurality of active region units parallel with each other and extending along a first direction;
• and
• a second active region disposed at an outer side of the first active region, the second active region comprising a first edge extending along a second direction and a second edge extending along a third direction, and the first edge and the second edge directly connected to a portion of the active region units, wherein the second active region comprises a plurality of first openings, and the first openings are disposed on the second edge;
• and
• forming a shallow trench isolation in the substrate, the shallow trench isolation surrounding the active structure.