Method of manufacturing semiconductor device having island structure

A method for manufacturing a semiconductor device, comprising:

• providing a substrate comprising an array region and a peripheral region, wherein providing the substrate comprising:
• providing a base having the array region and a peripheral region, wherein a top surface of the array region and a top surface of the peripheral region are coplanar with each other;
• and
• forming an island structure on the top surface of the array region of the base to form a stepped structure, wherein a top surface of the island structure is positioned above the top surface of the peripheral region of the base;
• performing a deposition process to form a passivation layer over the base and the island structure, wherein the top surface of the island structure and the top surface of the peripheral region are covered by the passivation layer, wherein a thickness of the passivation layer above the array region is larger a thickness of the passivation layer above the peripheral region;
• performing an etching process to remove a portion of the passivation layer over the array region, wherein the portion of the passivation layer is removed from the top surface thereof to form a first remaining portion and a second remaining portion, such that a top surface of the first remaining portion is positioned below a top surface of the second remaining portion;
• and
• performing a chemical mechanical polishing process so that the passivation layer has a substantially continuous surface over the array region and the peripheral region, wherein after the chemical mechanical polishing process, the thickness of the passivation layer above the array region is less than the thickness of the passivation layer above the peripheral region.