Method of forming a self-aligned stack gate structure for use in a non-volatile memory array

A stack gate structure for a non-volatile memory array has a semiconductor substrate having a plurality of substantially parallel spaced apart active regions, with each active region having an axis in a first direction. A first insulating material is between each stack gate structure in the second direction perpendicular to the first direction. Each stack gate structure has a second insulating material over the active region, a charge holding gate over the second insulating material, a third insulating material over the charge holding gate, and a first portion of a control gate over the third insulating material. A second portion of the control gate is over the first portion of the control gate and over the first insulating material adjacent thereto and extending in the second direction. A fourth insulating material is over the second portion of the control gate.